Its your decision to refund, but if you do and there's any type of shipping claim, both parties have to work with the shipper in order to process any type of claim. If you refund the money before a claim is settled, you lose.
In the event of a claim, what I do is get the process started and tell the shipper not to send payment to me, but have it go right to the buyer. Then, I contact the buyer and give him all the info on the claim so they can follow the process themselves. This puts the buyer at ease because they can see what's going on and not wonder if you are telling them the truth. The buyer will also be required to fill out paperwork and make arrangements to get the amp back to the shipper. This way works well because you already got paid for the amp and you have leverage with the buyer so they follow through on their end, as well. The whole thing just takes care of itself.
I'm assuming, of course, that the amp is still in the US and a legit shipping claim can be made. If the amp is somewhere in S America, keep your money in your pocked and the above infor for future reference.
In the event of a claim, what I do is get the process started and tell the shipper not to send payment to me, but have it go right to the buyer. Then, I contact the buyer and give him all the info on the claim so they can follow the process themselves. This puts the buyer at ease because they can see what's going on and not wonder if you are telling them the truth. The buyer will also be required to fill out paperwork and make arrangements to get the amp back to the shipper. This way works well because you already got paid for the amp and you have leverage with the buyer so they follow through on their end, as well. The whole thing just takes care of itself.
I'm assuming, of course, that the amp is still in the US and a legit shipping claim can be made. If the amp is somewhere in S America, keep your money in your pocked and the above infor for future reference.