As we can't see the OP's transcript we can only go by what they originally said was the reason for contacting ebay and that was due to not being able to do the refund themselves. 

Hopefully, the OP won't also get hit with a dispute resolution fee.

No idea what the damage was  or how the OP attributed responsibility to the buyer, if the damage was in transit, was it covered against damage, was packing suitable, did the buyer receive the item damaged,

why was it returned, etc etc.

Can they write the loss off, self insurance......

so many unknowns

Found this in my travels -

To issue a partial refund:

1. Go to your Returns dashboard.
2. Select View return details beside the item.
3. Select Decide what to refund.
4. Select the percentage you want to deduct from the refund amount.
5. Add a message to the buyer explaining why the refund wasn't full.
6. Select Refund now.

If eBay steps in to help, we may ask the buyer to return the item to you. You will no longer be able to issue a refund to the buyer even if you qualify to give partial refunds under our seller protections.

How to handle a return request as a seller | eBay