UPS damaged 1 of 2 items, discarded damaged item, and delivered undamaged item.

Hi! I have shipped through Mercari many times, typically through UPS surepost, and have never had any issues. Until now. I sold 2 candles, packed them well, and then received a notification that the items were damaged and the recipient refused, and they were being sent back to me. (The receiver refused, the package appeared to be damaged. UPS will notify the sender with the details.)

I then got a notification that they were out for delivery the next day, and figured it must have been a mistake. Got the delivery notification, the buyer didn’t say anything or rate me, so Mercari completed the transaction 3 days later, and released my funds. Now, the buyer has reached out to me and said they only received one candle. I’m assuming one candle was damaged, discarded, and they delivered the one that survived. Is there anything I can do in this situation since the transaction is complete?