POST-FILING CHECKLIST: WHAT TO DO AFTER SUBMITTING YOUR GST/QST RETURN

Submitting your GST/QST return is only the first step of the reporting process. Many Quebec businesses believe they are “done” once the FPZ-500-V is filed, but several important tasks must occur after submission to ensure compliance, avoid penalties, and detect errors early. The post-filing phase is often where refund delays, payment problems, and audit requests originate — especially if businesses do not monitor their accounts. This post-filing checklist gives you a structured approach to follow once your GST/QST return is submitted so your business stays organized, compliant, and ready for any follow-up from Revenue Québec.

A proper post-filing routine helps confirm that your return was received, recorded correctly, and free of issues that could trigger reviews.

LEGAL AND REGULATORY FRAMEWORK

Under the Excise Tax Act and the Quebec Taxation Act, businesses must not only file their GST/QST returns by the deadline but also ensure that payments are made on time and that records are retained. Revenue Québec may review returns after filing, request documentation, or adjust amounts if discrepancies are detected.

Once submitted, your return becomes part of your official tax file, and errors discovered later may require adjustments or amended filings. Monitoring your online account and maintaining organized documentation are key legal obligations.

KEY COURT DECISIONS

Courts consistently emphasize the responsibility of taxpayers to ensure accuracy after filing. Judges have upheld reassessments where taxpayers failed to correct obvious mistakes or ignored notices from Revenue Québec. In cases where refunds were delayed due to missing documentation, courts ruled that the tax authorities acted properly in withholding refunds until full proof was provided.

These decisions make clear that the taxpayer must remain vigilant after filing and respond to all follow-ups promptly.

WHY CRA AND REVENU QUÉBEC FOCUS ON POST-FILING ISSUES

Post-filing is where many compliance problems surface. Common issues include:
• late payments despite filing on time
• refunds held for verification
• missing supporting documents
• mismatched totals between ledger and return
• filing numbers that do not reflect actual deposits
• late responses to audit questionnaires

Businesses that maintain a disciplined post-filing checklist reduce the risk of these issues escalating.

POST-FILING CHECKLIST: WHAT TO DO AFTER SUBMITTING YOUR GST/QST RETURN

1. Confirm receipt of your return
   Log into your Revenue Québec “Mon Dossier” portal to ensure your return shows as received and processed. Technical issues or submission errors can result in unfiled returns without your knowledge.

2. Verify payment status
   If you owe GST/QST, confirm that your payment was:
   • submitted correctly
   • withdrawn from your bank account
   • applied to the correct period
   Payment misallocations are common and may cause unnecessary balance owing notices.

3. Save a full copy of your return package
   Store:
   • the filed FPZ-500-V return
   • sales summaries
   • ITC/ITR summaries
   • bank reconciliation
   • POS reports
   • expense documentation
   • payment confirmation
   Organize everything in a period-specific digital folder for audit-readiness.

4. Monitor your refund status
   If expecting a refund, check your Revenue Québec account regularly. Refunds are often held for verification, especially if your claim is large or unusual. Prepare to provide supporting documents quickly.

5. Reconcile tax accounts immediately after filing
   Compare your general ledger GST/QST collected and paid accounts to the filed return. If discrepancies appear, investigate and correct them early to avoid cumulative errors.

6. Respond quickly to any Revenue Québec requests
   If you receive a questionnaire, information request, or verification notice, reply promptly. Delayed responses often lead to escalated reviews or delayed refunds.

7. Check for filing or payment errors
   Review your return to confirm that:
   • all taxable sales were included
   • input tax credits align with supporting invoices
   • no personal or ineligible expenses were included
   • no period was filed twice
   • no period was missed
   Correct any errors through adjustments or amended filings.

8. Update your accounting system
   Ensure your bookkeeping reflects the filed return:
   • reconcile GST/QST control accounts
   • update financial statements
   • record payments or refunds
   This keeps your books aligned with your official tax file.

9. Prepare for the next filing period
   Set reminders, update your calendar, and begin collecting invoices and sales reports for the next period. Strong habits reduce stress at the next filing deadline.

10. Review whether your filing frequency is still appropriate
    If revenue has increased or decreased significantly, you may qualify for a change in filing frequency. Quarterly or annual filings may simplify reporting for some businesses.

MACKISEN STRATEGY

Mackisen CPA supports businesses through every stage of the GST/QST cycle — including post-filing. We monitor your Revenue Québec account, ensure payments are applied correctly, reconcile tax accounts, and help address notices or verification letters. Our team prepares audit-ready documentation packages that speed up refund approvals and reduce the risk of disputes.

For businesses experiencing regular filing issues, Mackisen reviews their internal systems, identifies weaknesses, and implements solutions that streamline future filings.

REAL CLIENT EXPERIENCE

A retailer filed returns correctly but frequently had payments misallocated by the system. Mackisen intervened, reallocated payments, and prevented accumulating penalty notices.

A consulting firm had a refund held for verification. Mackisen prepared a complete supporting documentation package and obtained approval without further delay.

An e-commerce company discovered discrepancies between filed returns and ledger balances. Mackisen reconciled the accounts, corrected entries, and prevented future errors.

COMMON QUESTIONS

What happens if I discover an error after filing
You can file an adjustment or amended return. A CPA can help determine the best approach.

Does filing on time matter if I pay late
Yes. Payment deadlines matter. Late payments trigger interest and penalties even if the return is filed.

Why was my refund delayed
Refunds may be held for documentation review, even when everything is correct.

Should I wait until year-end to reconcile GST/QST
No. Monthly reconciliation prevents major year-end adjustments and audit risk.

Is Mon Dossier necessary
Yes. It is the main portal for notices, refunds, and payment verification.

WHY MACKISEN

With more than 35 years of combined CPA experience, Mackisen CPA Montreal helps businesses stay compliant and organized after filing their GST/QST returns. We ensure payments are applied properly, refunds are processed smoothly, and discrepancies are handled early before they become audit issues.