What to do with partial refund request?

[depave-13]

I recently sold a watch for quite a bit and listed it as not working parts or repair only. Pretty much an antique novelty item... however my buyer is requesting a partial refund for repairs because I only stated it didn't work in general and not that it was damaged? I'm very confused. They want to keep it but want money back to repair it. What would you all do? They want 15% of the purchase price back. 

[hollysfinds]

I would not get into a back and forth with the buyer. 

If they are not happy they can return for a refund - period.

If they want to repair it then they can pay for it.