When a Vietnamese e-invoice is wrong, the fix depends on two things: what is wrong — a name, an amount, a tax code, the whole transaction — and how far the invoice has gone — whether it has been coded by the tax authority, sent to the buyer, and declared by either side. The rules provide a small set of routes: notifying the error, issuing an adjustment invoice, issuing a replacement invoice, and in limited situations cancelling an invoice that has not yet been sent. Choosing the right one is most of the work.
The wrong route rarely looks wrong at the time. Deleting an invoice in the ERP and issuing another feels tidy; the tax authority, which already holds the first one, sees two sales. This guide sorts the errors foreign-invested companies most often make and the route each usually takes, so that the finance team can decide in minutes rather than by email chain with the service provider.
The rules, and the three questions to ask first
Error handling is set out in Decree 123/2020/ND-CP, amended by Decree 70/2025/ND-CP, with guidance in Circular 78/2021/TT-BTC. Decree 254/2026/ND-CP and Circular 91/2026/TT-BTC on e-invoices and electronic documents have applied since 1 July 2026; we do not summarise them, and any error procedure written earlier should be checked against them. The routes below describe how the system has operated in practice; confirm the exact steps for your case in the current text or with your provider.
Before choosing a fix, answer three questions:
- Has the invoice been coded and sent to the buyer? An invoice caught before it reaches the buyer has more options than one the buyer already holds.
- Does the error change the tax? A wrong address does not change VAT; a wrong price, quantity or rate does.
- Has either side declared it? Once the invoice is in a filed VAT return, the fix has to be reflected in a later return, and the buyer's return too.
A map of common errors
| Error | Changes the tax? | Usual route |
|---|---|---|
| Buyer name or address wrong, tax code and amounts correct | No | The rules have allowed a lighter route: inform the buyer of the error without reissuing, and notify where required. Check the current text. |
| Buyer tax code wrong | Yes — the invoice points to a different taxpayer | Adjustment or replacement, agreed with the buyer |
| Price, quantity, VAT rate or amount wrong | Yes | Adjustment invoice (increase or decrease) or replacement invoice |
| Coded invoice with errors, not yet sent to buyer | Depends | Notify the tax authority of the error in the prescribed form and issue a correct invoice |
| Same sale invoiced twice | Yes — revenue doubled | Treat the duplicate through the prescribed error route; never simply delete it |
| Sale cancelled after invoicing | Yes | Handle through the prescribed route with written agreement of the buyer |
| Invoice issued by, or to, the wrong group entity | Yes — wrong taxpayer on one side | Correct in the name of the entity that issued it; the right entity then invoices properly |
The table is a map, not the text of the rules. Its purpose is to stop the most common reflex — cancel and reissue — and to send each case to the right question.
Adjustment or replacement: how to choose
Both routes leave the original invoice in the system and link the new document to it. The difference is in what the new document says:
- An adjustment invoice shows only the difference — the increase or decrease in quantity, price, VAT and total — and references the original. The original remains valid as adjusted.
- A replacement invoice restates the whole transaction correctly and references the original, which it supersedes.
Adjustment suits a single wrong figure on an otherwise correct invoice, especially where the buyer has already declared the original. Replacement suits invoices with several errors, where a clean document is easier for both sides to understand. Whichever you choose, the buyer should agree in writing, and the agreement should state the error and the correction. Keep it with both invoices.
Timing of declaration follows the correction. Under the tax administration guidance, an adjustment is generally declared in the period in which it is made rather than by reopening the original period; confirm how your case is treated, especially across a year end. The adjustment follows the VAT rate of the original invoice.
Duplicates and cancelled deals
Two errors cause more trouble than their size suggests.
Duplicates usually come from interfaces: an ERP resends a batch after a timeout, and the provider issues it twice. The tax authority now sees double revenue for that customer. Handle the duplicate through the error route the rules provide, with the buyer informed, and fix the interface so that a resend cannot create a second invoice — for example by making the ERP document number a unique key at the provider.
Cancelled deals are commercial: the customer withdraws, a shipment is refused at the gate, a service is not performed. If the invoice was already issued, the cancellation must be documented through the invoicing rules with the buyer's written agreement — not by deleting the invoice in the ERP. Where the customer has already paid, the refund should follow the same documentation.
In both cases the risk is not the error itself but the silence around it. An unexplained second invoice, or an invoice that "disappeared" from the ledger but not from the portal, is exactly what reconciliation-based checks by the tax authority are built to find.
Invoices issued by or to the wrong entity
Groups with several Vietnamese companies — a manufacturer and a trading company, a head office and a branch with its own tax code — regularly issue invoices from the wrong entity or to the wrong customer entity. The customer's procurement system has one vendor record for the group, or the sales team picks the entity it used last time.
Each entity is a separate taxpayer, so this is not a cosmetic error. The entity that issued the invoice has reported revenue it did not earn, and the right entity has not reported revenue it did. The correction happens in two places: the issuing entity corrects its own invoice through the prescribed route, and the right entity issues a correct invoice. Where a customer entity was wrong, the same logic applies from the buyer's side, and its input VAT depends on the correction.
The same discipline applies when you are the buyer. If a supplier sends an invoice with your wrong tax code, a wrong price or a VAT rate you did not agree, do not book it and "fix it later". Tell the supplier in writing, ask for the correction through the proper route, and hold the input VAT claim until the corrected document arrives. Accounts payable teams that quietly correct figures in their own ledger end up with a VAT return that no longer matches the supplier's invoice data.
Prevention is cheaper: map each customer contract to the issuing entity in the ERP, and block invoicing when the contract and the entity do not match.
Keeping the error rate down, and where to check
A correction is not a failure; a pattern of corrections is. Track three numbers each month: invoices corrected as a share of invoices issued, the causes (master data, interface, sales input, commercial change), and the average time from discovery to correction. A rising error rate usually points to one fixable cause — a customer record not updated after a move, a product code without a Vietnamese description, a new salesperson.
Places to check:
- The tax authority's e-invoice portal — every original, adjustment and replacement invoice with its status, and any error notifications sent.
- The taxpayer information lookup — the buyer's current name, address and tax code before you reissue anything.
- The company's e-tax account — the VAT returns in which corrections were declared.
Keep the original, the correction, the buyer's agreement and the internal approval together for at least 10 years, the minimum retention for accounting documents under the Law on Accounting. For the commercial side — discounts, rebates and returns — see the guides in our value added tax section.
Frequently asked questions
Can we just cancel a wrong invoice in the ERP and issue a new one?
No. Once the invoice exists in the tax authority's system, cancelling it in the ERP changes nothing there. Use the route the rules provide for that kind of error.
The buyer's address on our invoice is out of date but the tax code is right. Do we reissue?
The rules have allowed a lighter route where only the name or address is wrong and the tax code and amounts are correct: inform the buyer without reissuing. Check the current text before relying on it.
Should we adjust or replace?
Adjust when one figure is wrong on an otherwise correct invoice, especially if the buyer has declared it. Replace when several details are wrong and a clean document is clearer. Agree the route with the buyer in writing.
Our interface sent the same batch twice. What now?
Handle each duplicate through the prescribed error route, inform the buyers, and fix the interface so a resend cannot create a second invoice.
We invoiced from the wrong group company. Can we move the invoice to the right one?
No. The issuing company corrects its own invoice and the right company issues a new one. Each is a separate taxpayer.
In which period is a correction declared?
An adjustment is generally declared in the period it is made, not by reopening the original period. Confirm the treatment for your case, particularly across a year end.
