worst service ever from MTN

my wife upgrades contract via mtn's call centre , the agent loads an anytime 200 when my wife asked for a mychoice 100. she only found out a few days later when she called in to try and set a bill limit. the guy she spoke to says that the lady that wrote up the contract is unavailable or not answering her phone, he will email her to call back and amend the contract...after 3 days no call back, so my wife calls in again and another message is to be left for this person to resolve the issue. call in again 30.11.2015 still another message will be sent to this person, ask to speak to supervisor and guess what...no supervisors available. get put throught to customer service and speak to elroy ref*** supervisor Luciano is on a call will get him to call us...and still no one has called to date ....so now the debit will go off for the incorrect amount and who will fix that ..why is MTN not responsible...i told my wife she should have not upgraded with MTN...