mtn poor service

Mtn network is horrible a had my number for more than ten years, two months back someone did a swim swap with my number i tried to call mtn to report but the options are not available to choose what i want to do , i visited their branch in church square they asked for affidavits i went to the police station i got one the swim swap was reversed , a month later again the same thing happened. In my understanding when someone does a swim swop they ask security questions i fail to understand how is mtn allowing this. The people even tried to change my login details for the bank account, i saw it immediately i reported to my bank.