Any recourse for claim that one item is missing from order?

FBM. Had a customer message us that one item was missing from their order. They ordered two items. When we checked shipping weight, there is no doubt that both items were in the package. We used buy shipping.

Is there any way for us to do anything about this other than just sending them a replacement? It fees scammy, but I'm not going to say I've never received a package that has been somehow opened and then retaped. Usually USPS, which is how this was shipped.