MTN & Mondo Mobile are the worst service providers!

I had the worst experience with MTN and Mondo.It all started with the wrong device and wrong contract i signed up for.After a month of back and forth i asked for the contract to be canceled.This happend 3 and a half months ago and i am still paying a monthly subscription and just this morning MTN deducts R5000 from my account.This is unacceptable im being ****** by MTN!!!!!How do you just take money from consumers like this.