Wrong Order

I bought three quarter bedding set and the delivered wrong size. The duvet covers are for single, the night frails are for double bed and curtain have different colours. I ordered in November and they delivered it first week of December. I didn't open the boxes the same time decided to open it on the 24 December only to find all this wrong sizes.

I called them to to make an exchange but I was told that the 14 days period passed. But now im sitting with a set of different sizes and I can't use it. I only wanted to exchange. Bad service