my sim was **********ly upgraded

A ********* upgraded my closed cellphone contract online and the phone was couriered to him or her. I was only aware when Vodacom demanded payment from me. i indicated to them that i did not upgrade the contract and i received no phone. they then requested me to fax an affidavit of which i did but there were no updates on the matter but i assumed the case was finalized. i was surprised when i app**** for a home;loan and i was told to settle my matter with vodacom. When i contacted vodacom they referred me to their attorney who gave me a fax number that seemed not accepting faxes. my question is who upgraded the contract and where did Vodacom deliver the phone and which online account was used to upgrade. I never registered an online account with Vodacom. this matter should be thoroughly investigated and i need a feedback...