I am sorry ( former scammer )
I admire your honesty and repent however like Falmear said, some wrongs just can't be undone. Half of those you scammed quit and forgot you by now, giving money back to them even if you find them won't do much. I suggest you give your money away to the needy etc.
And to the one or two guys that are preaching about the OPs courage or whatever, just stop? I would understand if you actually knew the guy you were defending, but for all you know he could be a huge conman (or an extremely bored person) so you should just calm down.