Although you are allowed to put no returns - this only applies to "change of mind"

If you read some of the posts in this board, you will see that the seller will never win a "not as described" dispute.  Do not ask ebay to step in - they will side with the buyer every time.

You can request the item be returned, but then you will be out the postage twice

Or you can refund, and block the buyer from buying from you again.   I know it's unfair.

Some other sellers may have a suggestion.