telkom mobile account

I received a call in March from a person called Thembelihle Ndokweni from Pinetown she was promoting sum sung tablet the company she was working for was Telkom mobile. I was interested in buying the phone I gave her my details and I was waiting for the phone to be delivered but the phone never arrived, What happened my account was debited on the following month on my pay day by R150, next month it was R277, the following was R874, R1500, R427, R776, then I went to my bank ABSA the money was reversed, they traced the company contact details and they found out that was Telkom mobile ,then they advice me to change my banking details. after changing my details I received a call from a company NU debt management this is their number *** the person who was calling me was Nonhlanhla Mofekeng and she said I am owing Telkom mobile , I explained to her what happened and I never bought anything from Telkom mobile and she said I must send her ,my bank statements, affidavit stating that I never opened an account at Telkom mobile, proof of resident and my id copy. But the problem was that wasn't sure whether they are robbing me again and she said I call Telkom to verify.