To help us pinpoint exactly what is happening, could you clarify the specific issue you're experiencing with online credit card payments for invoices?
If your customers' payments aren't going through, it is often due to authorization steps or missing billing information. A quick way to troubleshoot is to ask them to try a different card to see if that works.
If you encountered an error message or experienced a different issue, please share the details in this thread so we can help you find the best way forward.