There is an Aransas Life and Health Insurance Guarantee Fund that SHOULD eventually protect you and pay the claim. BUT the doctor will say I want the payment NOW and I renedered service to you not the insurance company.
You may have to pay the doctor and when he is eventually reimbursed by the Fund he can credit you.
ONE POINT: The doctors generally agree to take a VERY REDUCED fee from the insurance company. For example, if their "normal fee" is $600 they may have agreed to accept only $250-400 for the exact procedure on plan members. That's all you should have to pay the doctor now.