Vodacom Blacklisting me over ********** contract

Vodacom began debiting my bank account in June 2017 **********ly. I phoned them and I was informed that a contract was taken under my name. I informed them that my identity was ****** and I never took out a contract with Vodacom. They kept sending sms's and calling me saying I owe them over R20k. I repeatedly told them that this was a ********** contract taken up. They told me to submit an Affidavit as well as a copy of my ID signed 6 times so they can compare the *****'s signature versus mine and conduct further investigations. The sms's and the calls stopped from Vodacom. Recently this year in 2018, I am now being contacted by Lawyers who work for Vodacom demanding this R20k bill from me! Further to that they have blacklisted me! I've sent Vodacom on their VVM email countless email to have this resolved to which they said I must deal with their lawyers they are no longer dealing with this case. I sent them all the documents they required. They clearly did not conduct any investigations and instead just handed me over as though I owe them. This nightmare has been going on for over a year now!