Why must I wait

I went to a doctor on 19 May 2020 to have my asthma checked out and the progress of how my medication was doing. My doctor asked for cash upfront. I paid R1900.00 cash. They asked me to send the claim form to Discovery. I then get told that I am only getting R1192.00 from the claim. The other is above scheme rates. The fact that I am not covered for the full amount is a concern. Asthma is a chronic condition. They should cover it in full. They then have a note on the payment date which was supposed to be Monday 15 June 2020. It is 17 June 2020 and I have not got my money. This is not how businesses should be run especially as I am the client. If they said 25 May 2020, I would agree, but to wait so long for money because of a claim, is ridiculous. They take my money before I earn it and then they want me to wait. I cannot accept this.