CAN buyer leave bad feedback?

[makingmiracles]

Ok, so I sold an item for £30 it was accurately described, brand new and I posted three pictures, including one next to a tape measure to clearly show the size of the item, I set all my items as no returns.
Buyer has msg me today to say item is considerably smaller than the one they were replacing(I'm pretty sure it has never been made in a larger size!) and could they return it.
Obviously this is hassle I don't want when I sold it clearly showing the size and I feel the responsibility was on them and they should have checked what size the one they were replacing was against the size shown on my auction page.

Question is, if I refuse the return can they leave bad feedback? I've 600+ 100% feedback and I don't want it ruined by a disgruntled buyer, what do I do?

It depends how they word the feedback really.

I sold clothing and my settings read "no returns" on the listing.

The buyer left negative feedback with the comment "wouldn't let me return item which didn't fit" I appealed this to eBay as my listing clearly stated "no returns", and they removed it.

However, if the buyer had left a comment along the lines of "unhelpful seller", I'm not as confident ebay would have removed the feedback.

If you want to maintain your 100% feedback, you'd be better off accepting the return tbh. Obv there is still a chance they could leave a neg, even if you do, some buyers are just arse holes, but the chance would be a lot smaller.