Damaged phone sent for Repair

On the 02 September I bought my wife a cellphone for cash which cost R799 with Edgars Melrose Arch. From day one it was giving her problems as phone was freezing. As I was meant to return it on the 7th Sept the phone got a small crack on 06 Sept. The phone was then functioning, however it kept on freezing. I returned and explained to Jerome (consulted) that the phone crack had no impact on the phone software(damaged software cause phone to freez). They booked the phone for repair and only returned today with the feedback that the repair company said the phone cost will be R592.00. I spoke to Simphiwe and the Manager there that I waited for more than 6 weeks 4 my phone and that it was hardly used. The diff for purchase price and repair is R200.00 which doesnt make sense for me as the phone was already damage when I got it. Edgars wont bear the cost, so I opted that they return my phone by the end of this week the way it was as there is no logic around the repair of a phone that I never even used for a month. There was no customer care from them as I was the one who kept on following up with them.Pls help...Regards:Jacob