Telkom Mobile has let me down

I have been a Telkom mobile customer for a number of years, using phone contract and wifi services. In all that time, I have been on a post paid contract and never had a returned debit order. After renewing my phone contract recently, I was switched to a top up contract without my permission or notification. I found this out on enquiring why I could not use my spend limit for in app purchases. I was told that the matter will be escalated and I will receive an answer in 48hrs, which of course didn't happen. On further enquiry, I was again given the same story with not so much as an sms to confirm that they have received my query, let alone done anything to fix it. I am very unhappy with the deterioration of service from Telkom Mobile