Contact the company who issued the vouchers, ask how they were ordered, if it was online ask them to provide the IP address of whoever ordered the vouchers, hand that plus copies of eveything to the police.
The reason I say hand it over to the police is not only that you might help them stop a scammer, but if the company is involved hen the police should be able to determine that. If they do anything at all... not sure how far they will take it.