It really depends on the nature of the "insurance company" and plan you had.
As the patient you generally are responsible for the bills, and the insurance company is responsible to pay you directly, or pay the providers for you, less any deductible or co-pay.
But some good news. If it is a duly licensed insurance company then there is a state guaranty fund that should cover claims; contact your state insurance department.
If it is NOT an insurance comapny, I don't know what else to say.