First thing I would do is demand that they put the reason for the denial of service in writing. Presuming you (and/or your insurance company) have already paid money to this same medical facility, explain that you need a reason in writing because you will be getting a refund on those payments. Record your conversation too. Whatever legal course of action you pursue, if your allegation it's not in writing, it didn't happen, without proof.
First thing I would do is demand that they put the reason for the denial of service in writing. Presuming you (and/or your insurance company) have already paid money to this same medical facility, explain that you need a reason in writing because you will be getting a refund on those payments. Record your conversation too. Whatever legal course of action you pursue, if your allegation it's not in writing, it didn't happen, without proof.