Hello, treasures, I am not an expert on everything here, but firstly id like to say, I am so sorry to hear tht this has happend to you.

did you send the item to this person registered, im asking can you prove actually having sent it to them?

If so, it actually sounds like, it was damaged on purpose perhaps, although we have no proof here.  but, If you have proof of having sent it, this is what i would do, wait for the buyer to open a dispute, or asking tell him he can go through the dispute to get his money back. You will need to provide proof that you send it to him.  He has no proof that he has send it back, perhaps, you can refund only the amount of the two items that came back in tact etc, whatever you feel is a fair amount. if you rather not, then go through the process and paypal will ask him to supply proof of having sent it back, it will be a bit messy for him i think. I dont suggest refunding any postage, or return postage in my opinion and if you do refund anything, make it for the amount of the two items received in good condition etc.  I have no idea, what i would really do in your situation, i guess being on the outside, i presume to have some answers, but whether they work for you, is up to you really.

wish you all the best with your customer