I understand how time-consuming it is for you, @Marichel. No worries. Let me get you the appropriate support in turning off the  Process credit card feature in QuickBooks Online (QBO). 

As we've already tried turning off this feature and still getting the box to tick or untick, I recommend contacting our Customer Care Support. This way, we can let them know the issue you've encountered, and they have the appropriate tools to assist you further. 

Here's how: 

• You can Chat with us. 
• We encourage you to review some of our commonly asked Payments questions.

The best way to contact the right person is to get help by calling us at 800-446-8848.

Please take note of the available support during these business hours: Mondays-Fridays, 6:00 AM to 6:00 PM PT. 

Additionally, I've added this article to learn how to check when QuickBooks deposits customer payments into your bank account: Find out when QuickBooks Payments deposits customer payments.

Feel free to reply to this thread again if you need further assistance managing your funds in QuickBooks Online. I'm always here to assist. Keep safe.