False promises and double billed

To say I am angry is an understatement!!!!!! I am generally a quiet person but MTN has seriously pushed me too far. As if it's not enough that I'm not given what I was promised when I upgraded my contract last year, MTN has decided to double my monthly payments and has even blocked me from seeing my statements and sometimes they don't even send me the statements. They would promise to get back to me but they have never done that regarding the false promise they made to the data I'm supposed to get, I let that slide. Now i have been billed twice for my contract!!! I am so done with MTN. I just want this contract to end and I'm never taking any data contract with them.