Would Comet have dealt with Marbles? I have never brought from Currys?

I am new to this, so hi. I am just looking at all my finances and to be honest its a bit of a mess, I am having issues with HFC and Marbles and would like some advice, like the above i brought a camcorder and tele from Comets in 2005 and had the "loan" transfered to HFC or Benifical Finance, the total cost was about £1000, I paid off a fair wack in the year but not all as could not afford anymore, to this day I am still paying £56 a month and my balance is around £1700!! I have now stopped paying and need advice if there is anything I can do, PPI claim back or something similar. Hindsight is a wonderful thing and I would have done it different, but over the last few years money has been ok, now its tough and I need to stop paying out to companies that have had there fair share! I am in the same boat with Marbles over a 3 peice sweet purchased in Oct 2005 and although the oringinal cost was only £1100 I still owe about £2000 to them. Any advice would be good.