This Anaesthetist Overcharges!

Husband went in for operation in 2014. Medical aid covers specialist at 200%. 2 months later it came to light that the anaesthetist charged more than the specialist that did the operation. The account was so overcharged that the medical aid paid only R2K of the R4K account. Contacted the accounts and told them that they got paid 200% and the rest was overcharged were told that the doctor is contracted out and that's just how it is. After this went backwards and forwards, told them they will not get payment as I was the only provider in the house as my husband lost his job. Then the accounts told me to not worry anymore that the amount had been WRITTEN OFF. Then 6 months later received a bill that requests payment as the amount was re-billed, saying that I should have paid off even just R10 a month. Now how can one pay on something written off... Now today another 5 months later and I receive a re-billing of the account PLUS - added to it my written off amount demanding now double the amount, so increasing the billing to R6K??