Disappearing Airtime Credit-Reference number ***9

I had airtime credit of R83 on Friday with the intention of purchasing the blackberry bis which i did but later found out from MTN that bis is having a problem at the moment so i must just buy normal data.I cancelled the bis and as at the time i had R83 remaining then i switched off my data for the whole day with the intention of topping up more airtime in the morning and buying normal data.On Saturday morning when i checked my balance there was a lousy R23 a whole R60 was gone.I tried to get hold of customer service and managed to get through after a while and was told that their system has not updated that i must call the after 2 hours which i did but this time i could not get through.I sent an email to the customer care department and got a response from a Jabu Shabalala yesterday who was forwarding my email to the 173 department .Till today no response and my airtime is gone.Thank God there are other good service providers who are cheaper ,i will be porting very soon.Please ask someone at MTN to look into this matter for me.I am a sudent and R60 is a big deal for me!!!