unable to cancel a contract

my daughter has left the country its 2 years now, on tuesday vodacom called me and said her account is in arrears and is on prelegal. i paid the money as i dont want her black listed and i have requested to have this so called contract cancelled. i have phoned vodacom more than 15 times. one of there consultants said my daughter needs to giv eme power of attorney and a copy of her id and i must go to a branch which i did, irene vilage mall theysaid they cant do anything i must send an email to vodacom and contact prelegal. i cant seem to cancel this contract as its not in my name, nobody wants to assist me , i get told to go back to the branch. i have sent numerous emails that vodacom hkeeps giving me. now they say its not my account so they cant help me. if its not my account why did they call me for money? how do i cancel this contract? my daughter isnt coming back and im not going to pay vodacom indefinately. what to do now ?