Bad Service - Cannot explain charges

I contacted MTN call centre on Sunday 20/09/2015 to find out why when I recharge my account via my cellphone banking , I receive a confirmation sms from MTN advising my account has been topped up with airtime I purchased and when i bought my internet bundles i also receive the confimation sms from MTN confirming. but once I make a phone call i receive a message that I dnt have airtime to make a call and my data remained the same as it was before i recharged it so I phone the first call centre agent advised I have open apps running which i advised is not the case as all has been closed, so i am transferred to the second agent WHO ONCE AGAING COULD NOT EXPLAIN THE BILLING SO again i was just passed along to a lady called lucresia who said she would wipe my internet account when I asked to explain what is running she could not explain to me and said ' I must listen to her \as she will only clear my phone and was short off . I am SERIOUSLY ****ED OFF because I loaded R60 airtime which just "dissapeared\"" without anyone explaining to me why MTN IS BILLING ME "