Hello there, @CASMachine.

I'd be glad to help you delete the invoice payments from Square.

If you connect Square through bank feeds, you can undo and exclude your transactions so it won't create duplicate deposits. I'll be glad to help you accomplish this. 

First off, you have the option to undo your transactions from the Reviewed tab. Here's how:

1. On the left navigation bar, click Banking.
2. Go to the Banking tab.
3. Choose your bank.
4. Go to the In QuickBooks tab.
5. Put a checkmark on the box beside the transactions you want to undo.
6. Select Undo above the Date column.

These transactions will then be moved back to the For Review section. If you want to delete it in QuickBooks, you can add them the to Excluded section. Here's how:

1. From the For Review tab, check the transactions that need to be excluded.

2. Select the Batch actions button, and click Exclude Selected.

However, if Square app is already synced with QuickBooks, transactions are automatically imported and there isn't a way to undo or exclude it. What we can do is to check the register and delete the square payment from there. 

I've added this article that can provide you details on how to combine multiple transactions into a single record so QuickBooks matches your real-life bank deposits: Record and make Bank Deposits in QuickBooks Online.

Don't hesitate to get back to us if you need further assistance. We're open 24/7 to help you out. Wish you and your business continued success of your business.