how do we find out who the bonding company is if the GC will not provide the information?
It's in the GC's best interest to give you a copies of the payment and performance bond, because the alternative would be for you to sue the GC directly. I would ask the owner for a copy of the bonds. Best practices is to request in writing and be sure to cc the GC on all correspondence. Not sure of what [governmental] entity controls the project? Sending out lots of letters to all viable candidates is one way to call attention to the GC's refusal to issue you timely payment.