Incorrect claim for hospital stay

I was admitted at Parklane clinic last year November for two nights. I received cc a call in March 2017 for an outstanding balance on the account. I contacted medical aid immediately to enquire about the shortfall. I was informed that the hospital case manager claimed for only one night instead of two. I contacted the hospital on the same day. I spoke to someone who told me that it's almost time to knock off and that my matter will be resolved by the case manager ASAP. In August again I get a letter from their collection department stating that I will be black listed if I don't settle the account by end September. Again I call the account department of the hospital and spoke to a lady that called Lindi, who was initially rude but eventually agreed that the hospital only claimed for a single night and said their system is down and she can't send me a copy of the claim submitted to Medical aid. She referred me again to the case manager department where I spoke to again a rude lady who refused to tell me her name and said that the case was handled by Yvonne, who would get back to me. She refused to give me any contact details for herself or that of Yvonne stating that it is personal. How can a work email be personal when it is supposed to be a tool of communication between the patient and admin? Park Lane clinic need to fire all their account staff and hire people who want to work and who know what customer care is. It is by the way the second time that this is happening to me.