Congrats on making your first post here in the Community. I can walk you through the steps of how to cancel your Merchant Services account linked to your QuickBooks Online (QBO) account. It's a simple process. Here's how:
Choose a reason and add any comment you'd like from the Reason for closing drop-down.
Click Submit when you're ready.
You'll get an email in one business day that verifies your QuickBooks Payments account is closed.
Afterward, you can still sign into your Merchant Services Center up until 12 months after you cancel. This allows you to view and download your reports, statements, and tax forms for a full year.
This should do the trick of canceling your QuickBooks Payments account. If you have any trouble along the way, don't hesitate to contact me. I'm always here to lend a helping hand. Wishing you and your business continued success.