Poor service and selfish sales personnel

I'm gatvol with MTN, and to be honest we are just blaming MTN for nothing. The problem is with the sales persons. They are just selfish and don't think about the clients. I asked nicely to cancel the previous contract before I commence with the new contract. But No, she decided to keep the old contract with the lost simcard. I'm paying double now. Worst part for something that I don't have. When you try to reach Contract department there's poor signal, they won't even bother to call you back. But go through new contract, they call back immediately with good signals, loud and clear. That is so pathetic.