Billing, Bad attitude, Poor Service, Damaged Goods

Hello, i took the phone on contract in May 2015, In September 15 the phone was collected on repairs up until now, they then informed me that i have to pay for the phone being repaired and i disagreed as the phone was still under guarantee, i asked that the account be cancelled and the lady i spoke to advised me that it is possible to terminate the contract at no cost until i received a call that my account is in arrears, from my knowledge i no longer had an account, thats when they informed me that even if i terminate i am still liable to pay, thats is when i said how will i pay for a phone that i am not using , a phone they are refusing to give me and yet they can call and tell me about my account being on arrears because they refuse to give the phone back, i told them in order to pay for free they should bring my phone back unfixed, i will fix it myself, i will not pay for repaires then pay for a phone that they are holding, when ever i call for the manager its either they are in a meeting or out, i never get an honest answear about the whereabout of the pgone and now they sent me an sms saying my account has been handed over, for what? kindly advice, what should i do about this