Broken Playstation 3 under their care

I brought a Ps3, TV and a 5.1 sound system in as a buyback on Aug 2014,I have been paying installments every month! I was late with payment Dec 2014,my TV and speaker system was sold...the ps 3 was still however behind the counter??Relieved I continued to pay instalments for Ps3 as usual, no problem! On Sunday 8th Feb 2015 I went to settle amount owed, collect my playstation as it only expired on the 13th of Feb 2015. Since my ps3 was in store since Aug 2014 I asked to please test for me to make sure all was in working order. It didn't even switch on and after the staff tried multiple times it showed a orange light.Immediately They took the console to the counter and informed me that I still need to pay what I owed knowing that my console was clearly broken! I told them that I was not going to pay a cent as the console was in their care. They refused to take responsibility and blamed the buyer saying he does not always check the products and I brought in a broken item! Fortunately the buyer who actually checked my items was there and confirmed, only on the 9th that it WAS checked as I was with and confirmed infront of the owner.A month later denying point blank any resolve!? *****?