MTN not with holding there part of the contract

My husband and i have been having endless problems since last year now with MTN. We get debited amounts that are not part of our contract and when you try and query it no one is willing to help. i have spoken to so many advisors on the 808 number and everyone just passes me over to the next person. The advisors say that they leave messages for managers to get back to me but no one ever does, and its just amazing how every time i phone in there is NEVER a manager on the floor !!!!!! how does MTN work like that ?????? i have worked in many call centres and there is always at least one manager on the floor. We have such problems with missing data and airtime. This is costing us thousands of rands ever month and yet MTN does not car. i have been a customer of MTN's for approx 20 years and it has never been this bad. Why does a person have to publicly have to name and shame companies before anyone is prepared to help