Credit cards fail to save, even our internal card to test, says re-enter information

I understand this isn't an easy process for you, @diziness. I'll help you sort things out so you can add the credit card account successfully.

I've checked our database and so far there's no known issue about credit card accounts failing to save. 

Sometimes the stored cache can cause browser-related issues. I suggest trying to open another supported browser's private window, whichever is applicable. Here are the shortcut keys to open it: 

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Safari: Command + Option + P

If you're able to add the account seamlessly, then you'll have to clear your regular browser cache. This will prevent unusual browser behavior moving forward. 

For future use, check out this guide about setting up a recurring sales receipt in QuickBooks Online. 

You can also read this module to know how you can manage sales forms in QBO: Customize invoices, estimates, and sales receipts in QuickBooks Online.

Don't hesitate to leave a comment below. We're here to assist if you need more help with this matter. Keep safe!