billing problem

good day <br> on the 1st of January i was allocated minutes instead of airtime i only realised this the past Sunday when i bought airtime and i have a negative balance. i called in your customer care spoke to Susan who advised she logged a request to billings department she will provide me with feedback she still hasn't i even spoke to a team leader that Sunday by the name of kelebogile still there is no feedback every time i call and ask to speak to Susan I'm being told she busy will call me back and she does not. i told kelebogile that it is not my fault that virgin mobile allocated extra minutes instead of 150 airtime, kelebogile kept on telling me it's my responsibility to check my airtime so it is not anyone's responsibility at virgin mobile to call me and tell me that they made a mistake with allocating minutes not airtime, even explained to kelebogile that I'm not going to incur any cost that the company did and i was not even informed up until i called because i could not use the 30.00 airtime that i recharged with, even that airtime i was told i will get it back by Monday but still i haven't got it back. no one is willing to assist me even Susan she hasn't called me back