Very bad service from Discovery Health - unpaid claim after clear indication that the bill would be covered in full

I have recently had a terrible experience with Discovery. Before commencing with a dental procedure, I phoned Discovery to ensure that it was covered by our medical aid. I was informed that it would be covered in full, however, upon submitting the invoice after the procedure, Discovery said they would no longer cover the expenses. I contacted Discovery who reviewed my previous (recorded phone call) and was informed that, while the procedure is not covered in my benefits, because the agent said it would be covered in full, the amount could be taken from my medical savings account to cover the costs involved. After submitting the required documentation twice and following up with Discovery 7 times, the bill has still not been settled. I'm not able to get hold of agents who have helped me and no feedback is provided. It has now been 2.5 months without any progress.