We have posted one fragile item, well packed at our very best but item boken on arrival.

Buyer opened a "Return Request". We replied the buyer with a good explanation.

Buyer kindly accepted to receive the item cost only; not postage fees. Therefore we only need to reimburse the part payment.
Our question is, without effecting any Seller's Performance, which is the best way process to follow from now on?

To credit the part payment to the buyer,
1. We can try logging in Paypal, go to that payment and make the part payment to the buyer back. By doing so, we will gain the credit of item fees from ebay but we are afraid this will end up being an alert to ebay to penalise us as a "return" on our Seller Performance (one bad stroke)
2. There is a little button on the "Return Request" for the part payment. Should we make the payment as part of the actions of the "Return Request"? We will end up receiving the same bad stroke on our record
3. Or simply get their bank details and deposit into the item fees?
4. At this stage, who will close the "Return Request? Are we responsible to? There is also a deadline to act this upon.

Thank you very much in advance.