Mtn shocking service

How pathetic is MTN? My aunt is a Sassa pensioner and MTN has deducted a payment even though she opted to pay monthly by going into the store. This is the second month in a row where they deducted after payment was made. R249 monthly contract has cost her R1000 in two months. She opted for no insurance and yet they deduct insurance. Who can i speak to about this shocking service. As a Sassa pensioner, she does not have the resources to cover these duplicate payments. And MTN just goes ahead and cuts her phone. We are at our wits end trying to resolve this issue.