I've never heard of a case in my country where promoters and referrals were sued. I have read of the government issuing them fines but it's typically related to false promotions or misleading advertisements (like on billboards).

Your best bet for success is to look for others like yourself, who lost money, and to find representation willing to go for class action. Then you pursue the business who accepted your funds. See, even if you bring your friend to court and win, your money's with the company and not your friend. Most court could ask is to ask him to return you his referral commission. That's my non-legal expert opinion.

You do have yourself to blame, after all. Hopefully you learnt something from this.