MTN SouthAfrica does Not wantto cancel insurance on expired contracts

My name is peter am afrustrated mtn customer, MTN SOUTH AFRICA is debting my bank account for insurance that is in someone else name. I asked them to stop and they are reluctand to stop the debt orders asking me to to tell someone in in whose insurance cover is in her names to council , but the money is going off my account. They have the id no .and names of the person who they claim to be covering her gadgets but continue to debt money from my account for insurance. I provided them with contract or policy numbers ie MTNAR472957,MTNCS472957,MTNEBD472957 BUT NOTHING HAS BEEN DONE ABOUT THE CANCELATION. Note that all these contracts expired and am under no obligation to insure the contract. I need help regarding cancelation of these mtn insurance policies and recover of the money *******ly taken from my acount on monthly basis