Suing someone in the Philippines probably won’t be worth the effort for an $18 product. And the FBI probably will not care much about a $18 international fraud.
You presumably have their shipping address, so you can look up their local police department and report it as general fraud. Eg. The Toronto police have an online reporting tool for fraud and scams: https://www.tps.ca/services/online-reporting/
If it happens to be a slow day, or the person is already on their shit list (eg. on probation) maybe something will come of it. Having the gloating emails definitely helps. Or maybe the report just goes into a file until this person does this for a more expensive item and then it gets pulled to prove a pattern of behavior.