So after 6 chat attempts and 2 phone call attmepsQuestion - why would there be a difference between the actual Business Activity Statement and the GST Summary Report -

Hello springbrook-west,

I understand you're having fundamental issues with your BAS in QuickBooks Online. Allow me to provide some information on why there is a difference in your BAS and GST Summary Report.

One of the most common reasons why there is a difference between your BAS and the GST Summary is due to an amendment. A GST amendment is a change made to a previous period that has been lodged, where the change has been made after the lodgement. Not only the amendment is tracked, but it'll also affect the current BAS lodgement.

If you've lodged your or previous BAS already, any changes you made to that period since the lodgement will automatically appear as amendments to the next BAS period to be lodged. You can see these in a list under the GST Amendment Report. Here's how:

1. Click on the GST tab.
2. Click on the Run reports tab.
3. Click on GST Amendments.

Another report you can check is to compare the Transactions by Tax Code and the GST Detail report under the GST tab. 

1. Under the GST page.
2. Click on the Run reports button.
3. Click on Transactions by Tax Code.
4. Double check if all transactions are coded correctly with a GST code.

If you see incorrect, missing, or duplicate transactions that could affect the BAS figure, you can request to unlodge the BAS period and make the corrections. Once done, you can relodge the BAS in QuickBooks Online.

To unlodge the BAS we'd recommend contacting the Customer Care Team. That way, they can help you with the BAS unlodgement request. 

Also, you can check this article to learn more about GST exceptions and reports in QuickBooks Online.