Call the insurance company and tell them you paid up front. Then fax or mail (some require original documents and fax is a copy, so may have to mail) your proof of payment and request the insurance company reimburse you.

If they don't comply, file a complaint with your state's Department of Insurance (DOI). Insurance companies do not like this and the law requires them to resolve your complaint as quickly as possible.

After they reimburse you, they can request a refund from the hospital/program.