A Business Owner’s GST/QST Journey With a CPA

A Montreal self-employed professional had been managing her own GST/QST filings for years using spreadsheets and basic accounting software. At first, everything seemed fine until errors began piling up. Refunds were delayed, deposits didn’t match sales, and Revenu Québec sent multiple notices questioning her filings.
What started as a “simple DIY approach” turned into a complex compliance problem. With Mackisen’s help, the business went from uncertainty to complete clarity and confidence.

This case study shows how switching from DIY tax filing to professional CPA support transformed a struggling compliance process into a smooth, audit-ready system.

The DIY Approach Begins to Crack

The business owner, a consultant with fluctuating income, handled everything herself:
• manually tracked sales
• typed GST/QST amounts into spreadsheets
• didn’t reconcile bank transactions
• mixed personal and business expenses
• guessed tax codes
• filed returns without proper documentation

Warning signs appeared:
• refunds took months
• Revenu Québec issued verification letters
• ITCs and ITRs didn’t match expenses
• entries didn’t balance
• mistakes repeated quarter after quarter

DIY filing quickly became stressful and unreliable.

The Breaking Point: A Refund Verification Notice

Revenu Québec requested:
• supplier invoices
• proof of payment
• contracts
• bank statements
• ITC/ITR schedules

The business owner could not produce complete documentation because it had never been organized. Refunds were frozen. An audit seemed inevitable.

How Mackisen Took Over and Fixed Everything

Step 1 — Full Accounting Diagnostic

The CPA team reviewed:
• software setup
• tax codes used
• sales vs. deposits
• missing receipts
• inconsistencies in prior GST/QST filings

Dozens of errors were identified.

Step 2 — Reconstructing Bookkeeping

Mackisen:
• categorized all income and expenses
• separated personal and business transactions
• downloaded missing invoices
• corrected duplicated entries
• matched deposits to invoices

The books, once a mess, became clean and reliable.

Step 3 — Correcting GST/QST Filings

The team recalculated multiple periods:
• rebuilding ITC/ITR schedules
• identifying incorrect claims
• finding credits the owner missed
• preparing adjustments for past filings

Proper filing restored accuracy.

Step 4 — Implementing Professional Accounting Software

The business shifted from spreadsheets to a structured, CPA-configured system:
• automated GST/QST codes
• monthly reconciliation
• digital receipt storage
• consistent reporting
• clear audit trails

Errors disappeared instantly.

Step 5 — Communicating With Revenu Québec

Mackisen handled all communication:
• answered verification questions
• submitted clear documentation
• resolved discrepancies
• secured the release of frozen refunds

The verification closed with no penalties.

The Outcome

Within weeks, the business:
• received all pending refunds
• corrected years of inaccurate filings
• restored compliance
• gained an audit-proof accounting system
• eliminated stress around taxes
• improved cash flow and budgeting

The owner went from overwhelmed too fully confident.

Key Lessons

• DIY filing works until it doesn’t complexity eventually outgrows spreadsheets
• Missing receipts and tax coding errors cause refund delays
• Proper software setup is essential for GST/QST
• A CPA can uncover credits missed for years
• Revenu Québec responds better to organized, professional documentation

Client Quote

“I was drowning in spreadsheets. Mackisen fixed my books, handled Revenu Québec, and now my taxes take minutes, not days.”

Common Questions

Can DIY bookkeeping work long-term?
Only for extremely simple businesses most outgrow it fast.

Will Revenu Québec penalize DIY mistakes?
If taxes are underpaid or documentation is missing, yes.

Can a CPA fix past returns?
Absolutely reconstruction and adjustments are common.

Will switching to a CPA save me time?
Yes dozens of hours per year.

Why Mackisen

With more than 35 years of combined CPA experience, Mackisen CPA Montreal helps entrepreneurs transition from DIY bookkeeping to professional GST/QST compliance systems that save time, reduce stress, and protect against audits.