poor services

Around 2017 I received a call from MR price mobile consultants offering me a cell phone contract and I toll them , I don't need a phone because I do have one contract that I am paying and I refused to confirm my details as they already have on their side. after a week I receive a package from Mr price and I told them must collect it. they didn't do that. after a year the phone didn't work and I call them to collect it for repair because It was under a warranty again they refuse and I spot paying them because the phone was not working and I didn't use their benefit . Now I received a calls from daily credit collection , they say I must pay the remaining balance of 700.00 . My question I will pay this 700 for what because I didn't enjoy any benefit from the day they refuse to repair the phone.