It actually should be $0, but I believe also my last fee was around $50.
And by the way, you don't have to process a fraudulent order to get hammered with the chargeback fee. I had a customer who returned merchandise to a wrong address (someone completely different), she requested a chargeback because we didn't refund her for the merchandise we never received. The bank took the money back from us and we got the chargeback fee.
Later we got the chargeback reversed, but we could not get the fee refunded.