American Family Care complaint: AFC refuses to refund my $15 copay

I went to my local American Family Care on November 12, 2018. They required I pay the standard $15 copay, otherwise they’d not let me get beyond the locked door be seen by a doctor or nurse. After being seen I asked about getting a refund for the $15, because no copay is required for a wellness check nor a flu vaccine. I was told I had to call AFC’s billing dept. I called they said they’d not refund my money until they were paid by my Humana insurance. Humana paid them. The check was cashed on November 29. However for 3 months AFC has REFUSED to reimburse me my $15. All pertinent info has repeatedly been provided by Humana to AFC, including check number etc., but they still refuse to give me my $15 back. It’s been 3 months. Then yesterday for the first time in 3 months I was given a new excuse. I was told I was required to pay a copay, because I had more done that just a wellness check. The flu vaccine I received also has no copay.
Please refund my money ASAP, otherwise I’ll NEVER go to AFC again I’ll complain to the BBB Angie’s List.