Stop harassing me Vodacom

I have been a vodacom prepaid customer for almost 20years now , and have never been in any contract agreement with them. I was puzzled when I received a debit of R1300 the 1st month and the following they doubled it to R2600 and some change, because I reversed the 1st one. I then decided to go to vodoshop to enquire about these debits since I have no business whatsoever with vodacom, I was so shocked when they told me it's for a contract phone I took with them... I then asked them to show me ,the Identity document , payslips and bank statement attached to the contract cos in my belief you not able to take up a contract without any of these documents, to my surprise there were no documents attached which then proved that it's an inside job. I was then told I needed to go write an affidavit and attach it to the form they gave stating what has happened and I did all of that even received a response that the issue was resolved but up to this day they still harass me with calls demanding that I make payments. It's over 6 months being harassed by Vodacom for a contract I never app**** for.