Netcare Accounts Department make me a bad debtor

My daughter's hospital claim was rejected by our medical aid. We appealed this with the CMA and in the meantime I contacted Netcare accounts department to settle the bill and on 8 August 2017 I made contact with Felicity Swartz she said I should send 3 months bank statements, etc. and she would send my file onto her manager to set-up a payment plan. I also asked her for the invoice for the hospital. Over the last seven months I have being trying to get an invoice and payment plan from Netcare accounts department. Felicity didn't answer her emails or calls and when I spoke to the her this year she said she was no longer with that department for the last year??? I spoke to Thabo left a message with him as Rebecca was the contact. No call. Spoke to Riccardo van Buuren, sent him all my emails and request for an invoice and payment plan, he acknowledge email and no response back from him. Spoke to Stearns Maluleke, he sent me an invoice and we agreed on a payment plan. I sent him proof of payment and he confirmed that my account was handed over to collections. I was furious as due to the Netcare accounts department inability to do their jobs I was now a bad debt. I spoke to Koos, their supervisor and he assured me that he will arrange for Lerato to send me an AOD and will remove me from the collections department. He assured me that this will be done. On the 4 April 2018 I receive a call from a debt collector for my account due to none payment. I spoke to Stearns again to sort this out and Koos to call me back.