Mtn Debiting my Account extra

I Have done an upgrade with mtn in May my new contract package should have been R479 but Mtn debited me my account in JuneR729 not deducting the SMS's and the Data that comes with the Package. called them in June they said that they will discount me the money in the new month. Now in July I get a bill of R776 there was no refund done on my account and now charge me for data worth R227 which was not used as i had data bundle on my account and once that was used i had airtime of about R600 that was being used as data. so how could i have used data of R227. i call the call centre they tell me they offline i must call back in and hour. if i have used R227 worth of data what happened to my 600 airtime that I had on my account that is not there anymore. They need to do a refund to me or something as this can not be going on, on a monthly bases. i have been a customer for the past 10 years and there service levels have dropped drastically. they have that don't care attitude the call centre is busy all the time meaning that a lot of people experiencing the similar problem and yet no change is being made.