Non payment of claim

My husband had a procedure done on 28th October for which we paid an admission fee, which we claimed back from Discovery on 12th November. We were not paid because apparently we only sent a receipt and were asked for a full account. As soon as I received the full account I forwarded it to the claims adjustment department on the 7th December. Their response was that the request would be processed within the next 2-3 working days. Reference number ***. I have not heard from them since and after several frustrating calls to your call centre and at least another 4 reference numbers we are still no further on.