Pathetic Service From Accounts Division

My wife had an operation performed at Carstenhof Hospital and the treating ER CONSULTING - DRS HOLT AND PARTNERS overcharged. The medical aid paid their agreed rate and requested the treating Doctor to provide motivation letter for overcharging and file notes so they can settle the balance. I have been in contact with ER CONSULTING for months and month and they can't provide the hospital file notes and motivation as required by the medical aid. Worse, ER CONSULTING has been harassing me with endless SMS and email threatening to have my name credit listed for the account balance while they're the one failing to provide just two documents. All they say is that I should pay and claim from my medical aid.. How am I going to claim without the same documents they're refusing to provide or they don't have. This is pathetic service and very disappointing for a huge company like that. Provide the required documents so that the balance can be settled.