Refuse to pay my ante natal class

I went to Unitas Hospital for an Ante Natal class in November. I had to pay R950 up front and claim back from Discovery. I checked online and my package covers this as well as giving me vitality points. I attended and received an invoice and receipt. I submitted this to Discovery and heard nothing back all of December (i was on leave so had to follow up in January). They had apparently not received this claim. I sent it again, after a week it was rejected. I followed up again, apparently the code was not correct. I needed to contact the hospital to get the correct code. The hospital said this is the code they use for all clients, and they have never had a problem before. I called Discovery to tell them this they said sorry they cant help me unless they get a correct code. I called the hospital they gave me an amended invoice with another code, i sent this on to Discovery after a week, rejected AGAIN. Wrong code, AGAIN, I need to fill out a special payment form, which i did, and guess what REJECTED AGAIN, reason being \The reason for this is that the sister is not allowed to bill for that specific treatment under his or her practice type\" Please resolve this."