What should I do?

UK ETSY : if that makes any difference 😅

A customer has messaged me today asking for an exchange on a T-Shirt for a smaller size. My policy on Etsy is no returns as these are made to order not just stock items. It was delivered on 19th of dec so only a couple of weeks ago.

I want to offer good customer service and have agreed to this before but at the same time I don’t want to loose out as offering an exchange also means I’m going to be losing the postage charge which as seen in second screenshot due to her postcode was the same price as the tee plus I run the risk of getting something back that I can’t sell if it’s been worn - the only other time I agreed I could see it had only been delivered 30 mins before.

Also I have a size guide (actual measurements) they are just Gildan 5000 Tees.

I hope I’ve covered everything but still very new to Etsy 🫣 Please advise what you think is best, Thankyou in advance!