******* from Vodacom

I bought a cell phone at Jet Store King William's Town . It was a pre paid phone not a contract. Sometime in 2014 some one phoned me and introduce herself as staff member from Vodacom. She pursued me to allow them to give me air time for R60 and pay for R30 every month.I accept that but later i noticed that they deduct the money but they don't send the airtime.I tried to stop them from deducting from my bank account but in vain. Instead some one phoned me & told that they are going to upgrade my airtime.I beg the lady not to because i am struggling to pay now and she told me that they are going to upgrade because i can afford. Later i notice that they deduct R144.per month from my bank acc.I decided to move from F N B to Standard bank .I also decided to move from Vodacom to M T N left my cell no behind as it was a contract no now. Now codacom said i owe them some moneyof R1.500 .Please help me in regard i never bought a contract from Vodacom it was my pre paid phone. My no was *** from Vodacom