Terrible Accounts Service @ Netcare Millpark

Due to cancer complications I had to go for treatment at the Hyperbaric Chamber in Netcare Milpark. While the treatment there was good the accounts department is terrible. My Medical Aid pre-approved 10 treatments. Millpark only submitted 9treatments and got paid for the 9 and now keeps on asking for the 10th payment. I have repeatedly ask them to submit the 10th treatment so it can be paid and they have repeatedly failed to do so. This was pre-approved with an authorization number. I even sent them emails from the medical aid stating they only received 9invoices.