What do you do with the phony requests from

Recently, we have been getting e-mail requests from “deaf” people, asking for a trainer for a group of their female relatives who will be arriving to me by taxi. The person requesting is never from the USA, and we know this is a scam. They are trying to give payment with phony means, then ask for a refund. When they get the refund, the original form of payment is declined, and the trainer is out the $. We would like to try and stop this charade. When we write back that these requests are being forwarded to the FBI, the chain of communication stops. Anyone else have a solution? I know that trainers are falling into this trap and losing big dollars.