They pretended to transfer to the exchange an item of value, and agreed to swap that item for a different item of value. They've defrauded the exchange / obtai

They pretended to transfer to the exchange an item of value, and agreed to swap that item for a different item of value. They've defrauded the exchange / obtained a benefit by deception, like writing a dud cheque or something. Fraud doesn't require "legally recognized money" to be involved. If you had some scam where you knowingly traded counterfeit collectable cards for real ones you'd be in trouble too.