I'm not going to be of any help with QB's Payroll, but is this a Bank you have made an ACH payment with before for any of your other Contractors? Maybe the issue is at the Bank's end.
Odds are they will not talk to you if you do not have an account there, but if you have a good repore with your contractor, have them call their bank and see if they can find out if the issue is indeed on the banks side.
