Still no feedback after several e-mail

I called the day was admitted at a clinic for my wisdom teeth removal to find out what amount they will pay for the anethetics as they quoted me R1700, they guy said they will pay R1500 and will be responsible for R200. When me bill came, the amount was more (R2100) and Discovery only paid R1300. I e-mailed them, as I work full time and not allowed to call, and they said that they will get the recording from the day I called in to ask how much they will pay and get back to me the next day, this now was almost a month ago. Since the amount is more I feel that they should have paid at least the amount agreed on and the extra that was charged. I also received a bill from another doctor for the amount my medical didn't pay, Discovery said that they haven't received the codes and I e-mailed them the statement I got with the codes and still haven't heard anything back from that as well.