Terrible customer service

Horrid experience, my medical aid referred me to them to get my fillings done. When I arrived there I was informed that everything will be covered by the medical etc etc. One month down the line I receive a bill of R600 because all of a sudden the medical aid is not covering everything. The medical aid said they have charged codes which the dentist knew were not covered. Anyway, called in to discuss with the accounts department to find out what's going on, I was very polite at first and a lady named Julie was so rude, just started getting aggressive from the get go, telling me that I'm walking around with the fillings in my mouth and now I must pay. Really pathetic service and there was no reason to be rude a client. Maybe Julie should stop misinforming customers when they walk in and stop being so rude to people. Pathetic human being.