most if not all people in the world are "afraid" of losing their hard earned money. The only option i see that you can use to show them is the point where it don't cost you anything except time and effort to sign up and be part of SFI and the last thing you can use is show them you got some money payed to you by you business SFI. If they still don't trust it then it is better to move on and look for other people that would join.
