Poor service from MTN SA

MTN SA is really disappointing..On the 2nd of December I went to MTN store to upgrade one of my contracts that was due for up grading. But coming to my surprise,when we tried to login the system and tried to update my information....already that contract was updated by someone on the 14th of November and he even collected the cellphone device at other MTN store .This means this is something that could have been prevented..And we submitted the relevant documents to open the fruad case,I was told the process will only take 21 days...But I am afraid that after the 21 days nothing was done on the case ,they never called me or even emailed me..instead they suspended my simcard number that I'm paying on the monthly basis. When I called them they said they haven't received any claim documents on my name and I told them we did submitted the documents at mtn branch with the guy who was helping me..So I was told to go back to mtn store to ask those guys to submit those documents,and when get there they showed me the proof that the documents were submitted and they resubmitted them again. On the 30th of December they suspended all my accounts again..I called them again to ask them why is my account suspended while I'm paying and plus I submitted the supporting documents for fruad case to be investigated. I was told that my case was closed because the ID copy I submitted was not certified, I asked them why is the case was closed and I was never called to submitte the certified copy of ID . I was told that mtn is not calling customers.So I am surprised that if MTN is not calling customers why are they always calling us regarding other services that they have but when is something serious they don't call us ,and how was I supposed to know if they needed something from me..I'm very disappointed and frustrated with this situation because is now negatively impacting my credit score and l wanted to upgrade that contract because I was using that data for my school work. It seems like MTN is not willing to resolve this issue because it's almost two months now and I haven't received any response from them.