Disappointing service and rip-off

In March requested my itemised billing for the month of December 2014 to be e-mailed to me. Since I never had this service as part of my package I was told I needed to write a letter and send a copy of my ID which I did. a month passed and I never received anything. when I called in to enquire I was told I never made any calls in December 2014. the funny part is my airtime got depleted that month and I was told the only record they have is of me recharging....but no calls were made. this is rather bizarre because December is a busy time I know I made call and had to recharge almost everyday. so since I never made any calls according to Vodacom, I would to be compensated for the money they took from my account. What happened to my airtime in December because I never made any calls. I still don't have my itemised billing after two months of requesting it. How bad is this service and I have been a loyal client for almost 11 years now. I am now tired of calling and getting the same answer but no billing sent. I have exhausted all my options, I spoke to a supervisor already and nothing.