MTN sucks

Greetings, as a loyal customer of MTN network i feel ******. I have been with MTN from 2008 up until now. My monthly bill is an estimate of R1100 but i am continually being debited over R1000 extra every month. Numerous contacts have been made to mtn with not one response from 4 case numbers. I will be pursuing a legal case since MTN continues to be *******