unfair bad service

its more than a two month now returned the mtn (summermobile) upgraded contract package but my upgrade not yet cancelled as i was told that the collection guy didnt give them RMA number but all document shows the collection of package. the upgraded contract is debiting even if i returned the package and no one is able to help me as ive send more than 3 people for help and they just read my emails and delete , now am thinking to reverse the debit so that they can call to fix their mess.