May I know what specific error you're facing when running your client's credit card? When a browser stored a lot of caches, it could cause problems like bringing up the data to your account or latency issue. As an initial step, you can press the F5 key on your keyboard to refresh the page.
If the transaction is still showing a $0 amount, I'd suggest getting in touch with our QuickBooks Payments Support so they can help check your account on why you're getting an error. Also, they have the tools to verify the $0 transaction by tracing the funds.
All account-related concerns are directed to our phone support for security purposes. Unlike in this public forum, they have the tools required to perform any escalations in the system whenever necessary on your behalf.
I'm leaving you these pointers to know the types of fees as well as how your monthly statement shows your processing activity by date: