New phone received, now dead and no warrenty

I have a phone contract of 24 months with Jabba Connect.<br> I had lost my phone and Jabba connect brought me a new phone which was not in an original box.<br> five months down the phone has stopped working and I have phoned Jabba Connect to ask them to repair the phone as I am still paying the contract. <br> Jabba connected responded by saying the guarantee for fixing the phone has lapsed as they are using the previous phone's 1 year guarantee. <br> This is unacceptable as this phone has been received from them five months ago therefore has not reached the one year guarantee. how do you place a guarantee of one year on a phone that was reported lost? Jabba connect is responsible for its repairs but refuses to do so saying I must repair it wherever I choose with my own funds.