I sent an invoice to a customer.

They are attempting to pay by credit card, but when running, it remains as "pending" on their end.

They contacted their bank, but the bank says they (bank) are allowing the charge, not blocking and that the issue must be with QuickBooks' processor.

When I view the invoice in QBO, it shows where it was "viewed", but does not show the associated transaction attempt, or that it's in pending.

Basically, they want to pay, it's stays in pending, their bank says it's my fault.