Inappropriate \Promotions"and Billings"""

I am a loyal customer of MTN and have been for a number of years. Firstly, my bank account was debited with an amount of R690.00. I have to date not received an account from MTN so I am not entirely sure what I am being charged for considering that I am on a top-up contract. I also noticed that all of a sudden my airtime is being used whenever I use certain services (whatsapp, internet, email etc.) despite the fact that I have data available. I contacted the call center, which I've been trying to get through to for a whole week, and enquired about my account (the consultant failed to explain what the R690.00 charge was for), she only said she will request that I receive my account via email. I then asked about the data/airtime and was told that MTN applies 'promotions' to customer packages and that MTN do not ask their customers whether or not they would like these 'promotions'. So, because I was unaware that this 'promotion' had been added to my account I didn't know that I can basically only use my phone during specific hours even though that is not the package that I signed for. These 'promotions' are of no advantage to customers as they do not work according to customers needs.