It is their fault if they think it is not what they want after purchasing.
If the description was full of the info to describe it properly then they did not read it properly before deciding to purchase.
It is your call on what you choose to do, but if they open a dispute for item not as described then they need to put in detail why it does not match the description and you need to respond with what they sent you claiming "great item, great condition but its not what I want, it looks to small for my wrist" and once it is once it is escalated to a claim paypal will view the message between you to decide the out come.
Depending on the value sometimes it is worth refund BUT this does not necessarily mean they will not neg you and some times it is worth taking the red dot when you have done the right thing as far as describing accurately.
