Where is my airtime disappearing to?

Yoh I'm really tired now indeed.<br> <br> You recharged with MTN don't make a call the next day \you have insufficient funds to make this call"even worse the lady shouts! I call the call center for enquiry voice prompt that my call can not be attended to try again later.<br> <br> I would honestly like to know what is happening with MTN lately. I have never spent so much on airtime like recently. Yesterday afternoon I check my balance I have a positive balance on data & airtime I log in internet usage after using the internet hawu I try making a call \""insufficient funds\"" I check balance R0.00 positive data but has depleted. I buy airtime don't make a call. I make a call this morning the next best thing Insufficient funds how so its getting ridiculous really... This is just few of the events that have been happening.<br> <br> """