Pathetic communication

I went for blood tests in June 2021 for a kidney transplant which is supposed to be fully paid for by discovery. NHLS charged R16 000.00 to discovery - which they paid. They charged R3800.00 to my MSA. (Thay they refuse to return) Then September 2021 I get an sms that I have been handed over for R4400.00. I have not recieved any invoices on the lastest amount (which I am now fighting)