It’s too late now, but I would say never send a replacement item when the buyer had given an incorrect address in the first place. Or… if you are going to do so, always send via tracked method so that delivery status shows under the tracking number.

Did you send the original item via untracked method? If so, you will never win an INR dispute because you can’t prove delivery.

Bottom line: if your items are primarily sent via untracked letter for instance, and a buyer claims item not delivered, you must refund the buyer in full. If you charge a little more (a few cents, for instance), you can add those few extra cents to your own “self-insurance”, and from this pot you should be able to cover the refunds for whatever small number of no -delivery claims you might have. Or… send tracked and charge p&p accordingly.