how to delete a deposit in QBSE because the customer did a bank transfer with NSF. QB shows it as paid on the invoice.

You'll first need to remove the paid invoice associated with the deposit, dfucinaro. Let me outline the process below.

Marking a paid invoice as unpaid isn't currently available in QuickBooks Self-Employed. Therefore, you'll want to make a Duplicate of it first and delete the paid one afterward. I'll add a screenshot of the steps you can follow:

Once done, you'll want to Exclude the deposit or transfer reflected in your transactions, as deleting transactions downloaded from your bank isn't possible. Excluded bank transactions will not be re-downloaded during future bank updates. In this scenario, you can manually re-import the deposit.

After you have completed the previous steps, you can proceed with processing your customer payments again. 

Finally, I've compiled a few additional resources for you to explore. These resources offer tips on entering sales income and expenses, quickly categorizing recent and past transactions, and deleting your online bank or credit card data:

• Manually add transactions in QuickBooks Self-Employed
• Create rules to speed up reviews in QuickBooks Self-Employed
• Delete bank and transaction data in QuickBooks Self-Employed

You're always welcome to ask follow-up questions about managing your sales activities or processing payments. We’re always here and ready to assist you.