Cell c giving u previously owned phone

Cell c direct called me for an upgrade and they gave me a phone which freeze and switch off they delivered the phone and expect me to go to nearby store. What is their use they give faulty handset its not the first time, unknowingly I wanted to put a screen saver and the dealer showed that the handset had one is it an oldset their giving me. I hv more than 10 yrs with this company but they *******.