No feedback regarding a refund due

After my transplant I had out of hospital bloods done. Knowing my savings was exhausted I paid cash. But it became too much as I done bloods every week and still continue 6 months later every now and again to check my organ function. Did enquiries with the medical aid and it turns out they were responsible for all the payments. They made payment so there was an amount due to me. Lancet wAs advised of this from myself and the medical aid. I recieved a call at the beginning of December advising they need to refund me I gladly hung on the line. Spoke to 3 people. The 3rd person sounded new as she kept confirming what she was telling me with the lady in the office. After all this I was advised that they can't do a refund when there are still outstanding a accounts Now like I said in the beginning I do bloods every week or every second week so basically I will never get my money back because on their systems there will always be an outstanding account. The last person I spoke to said she wAs going to hand my query over to a supervisor in the refunds depArtment who would get back to me the next day. It's been almost a month and no feedback or refund in my bank account.