HI Archie, how can a Quickbooks Checking client contact Green Dot bank?

Regarding a discrepancy of at least $20,000 (possible much more), I've been told by Quickbooks that 'we're not the bank,' then gave me a support number for Green Dot that does not allow me to talk to anyone there (I don't have the proper 16 digit card number, which apparently is not the Quickbooks debit card number. I can't use this Quickbooks checking account if I can't see what the balance actually is.

Thank you for any assistance resolving this matter.