I asked ChatGPT which vendor was blocking my ITC. It couldn't.
A general chatbot like ChatGPT cannot name which vendor is blocking your ITC because it has no live access to your GSTR-2B, IMS or the GST portal — it can only reason over whatever you paste in. Finding the vendor means reconciling your purchase register against 2B invoice by invoice and classifying each gap under Section 16(2)(aa), Rule 37 or Rule 37A.
"Just ask ChatGPT" is the reflex answer whenever a finance team wants to know which vendor is sitting on their input tax credit. Try it, and the model will explain Section 16 eligibility fluently — and then it will ask you to tell it which vendor you mean, because it has no way to look. This is the one question a general chatbot cannot answer on its own, and exactly why.
Why a chatbot can't answer this one
Ask ChatGPT "which vendor is blocking my ITC this month" and you will get a competent explanation of how input tax credit works — the Section 16 conditions, maybe a mention of GSTR-2B — and then a request for more information, because the model has nothing to look at. It has never seen your purchase register, your GSTR-2B, or your IMS dashboard, and it has no way to fetch them. The question isn't a knowledge question. It's a data question, and the data lives on a portal the model can't reach.
Paste your purchase register in and you've only moved the problem, not solved it. The model can now compare rows to rows, but it still has no independent copy of your GSTR-2B to check them against — so at best it repeats your own list back with commentary. It cannot tell you that a specific invoice never reached your 2B, because it never had your 2B to begin with. (The full breakdown of what a general chatbot can and can't do here — including where it invents section numbers with total confidence — is in ChatGPT vs Recoup.)
The three ways a vendor can actually be blocking your credit
"Blocked by a vendor" is not one situation — it's three, each governed by a different provision, each landing on your desk needing a different fix:
| What the vendor did | What it means for your credit | Provision |
|---|---|---|
| Hasn't filed GSTR-1 for the invoice at all | The invoice never reaches your GSTR-2B — under Section 16(2)(aa), that credit isn't available to claim yet, because it was never communicated to you | Sec 16(2)(aa) |
| Filed GSTR-1 but not GSTR-3B by 30 September following the year you availed the credit | The invoice reached your 2B and you claimed it, but you must reverse it by 30 November of that same year — and re-claim only once the supplier files that GSTR-3B | Rule 37A |
| Filed correctly, but you haven't paid them within 180 days of the invoice date | Not the vendor's filing at all — your payable is overdue, and the ITC you availed on the unpaid portion must be reversed with interest | Rule 37 |
Get these three confused and you either reverse credit that was never claimed, or sit on an unfiled invoice waiting for a re-availment that was never coming. (The full unfiled-GSTR-1 recovery playbook covers the first row in depth if that's the one you're facing.)
How to actually find the vendor, by hand
Without a tool that reads the portal for you, this is a manual, invoice-level exercise. In order:
- Pull your GSTR-2B and your purchase register for the period, side by side. Anything in your books that has no matching line in 2B is a candidate for the Section 16(2)(aa) gap — but check your IMS dashboard first, because a record you Rejected or left Pending by mistake looks identical to one the supplier genuinely never filed.
- Check GSTR-2B Table 5 for Rule 37A reversals already flagged. Since October 2024, your 2B for September of the following financial year auto-populates an "ITC Reversal on account of Rule 37A" line for every credit whose supplier hadn't filed GSTR-3B by the cut-off — the system has already done part of this identification for you, if you know to look at Table 5 rather than assume it's invisible.
- Age every unpaid invoice against its invoice date, not its due date. Anything crossing 180 days unpaid is a Rule 37 candidate — excluding reverse-charge (RCM) supplies, which are outside the 180-day rule entirely — reversible on the unpaid proportion, due in the GSTR-3B for the period immediately after day 180. This step needs your bank or accounts-payable ledger, not just the portal, because the portal has no idea whether you've actually paid a supplier.
- Name the invoice, not just the vendor. A supplier can be current on nine invoices and behind on the tenth. "Chase Meridian Castings" is a weaker ask than "chase invoice MC-4417, ₹1,12,400, filed in GSTR-1 but not yet in GSTR-3B."
The signature question, answered
Ask ChatGPT which vendor is blocking your ITC and, even with an export pasted in, the honest answer it can give you is a shrug dressed up as a caveat: it doesn't have your 2B, so it can't confirm anything against the source. Ask Recoup the same question and the answer looks like this: Anand Fasteners · AF-3390 · ₹94,600 · unpaid 187 days — Rule 37 reversal due. Not a general explanation of the rules — the invoice, the amount, the vendor, and the specific provision, because the answer comes from matching your actual bank, books and portal data, not from generating plausible-sounding text about them.
Why this is hard to do by hand
One overdue vendor is a five-minute check. A business running a few hundred active suppliers is doing the triage above — unfiled GSTR-1, Rule 37A reversal, Rule 37 non-payment — across thousands of invoices every month, against a 2B that changes each period and two separate deadlines that don't wait for anyone. That volume of invoice-level classification is painful to do manually, and the usual shortcut — sampling the biggest vendors and hoping the rest are fine — is exactly where credit quietly leaks.
Recoup reconciles your purchase register against IMS, GSTR-2B and your bank automatically, and where credit is stuck, it names the exact vendor and invoice holding it up — and which of the three rules actually applies — instead of leaving you to work it out line by line.
Related
ChatGPT vs Recoup for GST reconciliation
The fuller breakdown: no portal access, hallucinated citations, and the confidentiality risk of pasting your books into a chat box.
AI for GST reconciliation
What AI genuinely does well in reconciliation — matching messy records — versus the tax verdict, which has to stay deterministic.
Supplier hasn't filed GSTR-1?
The full recovery playbook when a specific invoice never reached your 2B.
This guide is general information, not tax advice. GST positions change; verify every provision, threshold and date against the current CGST Act, Rules, CBIC circulars and the GST portal before acting.
Stop asking a chatbot to guess
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