A common operational slip on the GST portal occurs when an accountant accepts an incorrect invoice, a duplicate bill, or an invoice belonging to another taxpayer on the IMS dashboard. If this mistake is spotted before filing GSTR-3B, you can re-open IMS, update the action, and re-compute GSTR-2B. However, once Form GSTR-3B for that tax period is submitted and filed, the underlying IMS action freezes.
Why IMS locks actions after GSTR-3B filing
The Invoice Management System became operational on 1 October 2024 to allow recipients to Accept, Reject, or mark inward supplies as Pending under GSTN IMS Advisory and FAQs. Prior to filing GSTR-3B, taxpayers can modify actions and generate a revised statement under CGST Rule 60(7).
When Form GSTR-3B is filed, the auto-drafted ITC from GSTR-2B is considered finalized for that period. According to the GSTN Additional FAQs on IMS dated 17 October 2024, records accepted and incorporated into a filed return can no longer be edited by the recipient on the portal for that past month.
Common mistake: Attempting to reject an invoice in IMS for an already filed return period will fail because the portal disables action buttons on locked records. Do not wait for portal changes: correct the credit claim directly in your next GSTR-3B return.
Step-by-step remedy when wrong invoice was accepted
When you have accepted an incorrect inward invoice and filed GSTR-3B, follow this practical correction sequence:
- Identify the excess ITC: Review your purchase register against GSTR-2B to find the exact tax amounts (CGST, SGST, IGST) claimed on the erroneous invoice. Compare records with our guide on handling IMS pending invoices.
- Reverse ITC in next GSTR-3B: Report the reversal under Table 4(B)(2) (Others) of your next Form GSTR-3B. If the credit was utilized against outward tax liability, calculate applicable interest under Section 50 of the CGST Act.
- Notify the supplier for GSTR-1A amendment: Request the supplier to amend or cancel the incorrect invoice. Under Rule 59(4A) of the CGST Rules (inserted by Notification No. 12/2024-CT), the supplier can file Form GSTR-1A after GSTR-1 but before filing their GSTR-3B to amend outward supply details.
- Action on fresh amended record: When the supplier files an amendment via Form GSTR-1A or a subsequent Form GSTR-1/IFF, the amended record flows into your IMS dashboard as a fresh document, resetting any prior action. You can then accept or reject the revised document correctly.
Worked example: reversing mistakenly accepted ITC
Consider a trading firm, Apex Traders, which mistakenly accepted a vendor invoice containing ₹18,000 IGST that belonged to another branch. Apex Traders filed October GSTR-3B without noticing the mismatch.
| Tax period | Action taken | Table in GSTR-3B | IGST impact |
|---|---|---|---|
| October 2026 | Accepted in IMS (INV-9812) | Table 4(A)(5) auto-populated | +₹18,000 (claimed) |
| November 2026 | Lock active; reverse excess ITC | Table 4(B)(2) manual entry | -₹18,000 (reversed) |
| November 2026 | Supplier issues credit note / amendment | GSTR-1A or next GSTR-1 | Fresh IMS record created |
Formula for net ITC available in the subsequent tax period:
Net ITC = Table 4(A) Eligible Credit - Table 4(B)(2) Reversals
If November eligible IGST from genuine inward supplies is ₹1,20,000, and Apex Traders enters the ₹18,000 reversal in Table 4(B)(2), the net available credit reported in Table 4(C) becomes ₹1,02,000 (₹1,20,000 minus ₹18,000).
Frequently asked questions
Can you change an IMS action after filing GSTR-3B?
No. Once GSTR-3B for that tax period is filed, the action taken on invoices included in that period is locked on the IMS dashboard.
How do you correct ITC claimed on a wrong accepted invoice?
Reverse the erroneously claimed input tax credit in Table 4(B)(2) of your next GSTR-3B return, along with applicable interest under Section 50 if the credit was utilized.
What happens when the supplier amends the invoice via Form GSTR-1A?
Under Rule 59(4A), if the supplier amends the invoice in Form GSTR-1A or in the next GSTR-1, the amended record appears on your IMS dashboard as a fresh document, allowing you to accept or reject it.
Check your own GSTR-2B
Catch discrepancies between your purchase register and portal data before filing GSTR-3B. Your GSTR-2B and purchase register files are read in your browser and never uploaded to any server.
Last checked: 23 October 2026. Sources: GSTN IMS Advisory & FAQs, CGST Rules Rule 59 and Rule 60.