wardrobe

Hello, I have quick question. Last year in November 2008 I bought wardrobe (big one with 3 slide doors) with private retailer. Now it is more than 6 month, and wardrobe just falls apart, backboard is support only against wall, roof is lift above sideboards, and recently I discovered that roof of the wardrobe one of the corners is broken in the place where rail was attached. Because of it none of the sliding doors are hanging properly, I am afraid that whole thing one-day will crash on me.
I want to go and complain to retailer, I want my money back because I have to buy new wardrobe. I am afraid that he will ignore me because I cannot complain any further like to head office etc. Can you tell what rights I have and what I can do to get my money back. I also bought with them over bed, bed frame and mattress.

Many Thanks for your response

Wardrobe came flat pack and people from that store offered to build it for me for extra £100 paid directly to them. I think they could damage the roof of the wardrobe but because wardrobe is very high up to ceiling I didn't notice anything until doors become very slanting. They haven't been straight from the beginning which I didn't like it because doors never have been tightly-closed and I had plenty of dust inside of the wardrobe, but now it looks like wardrobe just falling apart.

Many Thanks Tony

Do you know how can I contact with them or on which website I should looking for?