Unacceptable billing and a lack of transparency

Good day. My name is Neo Mdluli. I am extremely appalled by my experience with Gym Company. I have not been able to go to the gym, but I understand that they are supposed to debit an amount of R199 every month. I recently discovered that the money is not being debited every month as per agreement and took it upon myself, to call my gym branch and ask why this is not being done, as per signed agreement. The lady I spoke to for the first time went on to say that she also does not know why the money has not been taken for the past 7 months. I am not happy about this as I had given them everything that they had asked for in order for my membership to be processed. A few days ago, I received a letter from the company stating that I owe an amount over R8000. I would appreciate some answers because I do not understand how the bill managed to pile up for this long without anyone getting in touch with me. Should nothing be done, I will escalate this issue further.