No refund and no gift card for lay bye returns

I bought a suit on lay bye two months ago. I collected it yesterday and sadly I've lost some weight and the suit is doesn't fit. I went to exchange it and couldn't find my size. I'm told that I can't be given a refund because I bought the item on lay bye and shockingly they won't even give a gift card either. I've been told to keep the suit until there's something else in the store that I would like to buy, with in 29 days from now.