acc with legal dept though I have no acc with them

On the 7th of November my mom and I went to Vodacom Chris hani for her to apply for a contract to get the tablet and keyboard that was on special. She did not qualify because she was told that she had an account which has been handed over to their legal department. My mom said the last time she had an account with vodacom was over 5 years go and it was paid in full. The contract which was suppose to be a 2 year contract only lasted a year because Vodacom deducted money for a year then on the 12th month deducted the remaining balance in full instead of another 12 months. She communicated with them and they requested she send her bank statement for proof, which she did and they sent her a paid up letter showing a zero balance. I then proceeded to call vodacom who said they will sort that out. I submitted a complaint on the 9th November 2015 and to date no one has responded or given feed back