Online Returns

I ordered some dresses for a Christmas ball on 14/11/2018 and had them delivered to my local Hub Box, they arrived 22/11/18. Unfortunately none of them were suitable so I returned them 01/12/18.

They’re return policy states that a full refund will be issued for items returned within 14 days of receipt. They didn’t process my return until 09/12/18, (8 days after I sent it) and are trying to say that because it was returned after 14 days they only have to give me a credit note.

Where do I stand? I posted it back to them well within the 14 days, surely I can’t be held responsible for the fact it’s taken them so long to process it.

I have proof of when it was delivered to the Hub Box and also proof of my return via collect plus.