Am I on the wrong track?

I bought sheet music online as a gift for a friend, then realised he had the scores already. When I contacted the store, they insisted I had to pay postage to return the music. Surely I am entitled to a cooling-off period for the order and they have to pay return postage? No, unless their terms and conditions state otherwise. By law, the firm only have to cover postage if the items are faulty or not fit for purpose, which is not the case here. They have to refund the full amount you paid in the first place, plus postage, so you only pay once (for return post).