Poor service after making payment, de*****ed by MTN

I had a contract with MTN of 36 months, it has been paid off. The company kept deducting money in my account even after the expiry date, I stopped because I didn’t understand what I was paying for. They put my number under legal even though I have paid for it. This company is a **** and *****. My number is *** I don’t have any alternative number