I think making demands about transparency and shit is pointless. He's paying you back, albeit very slowly, why so many tears? Never "invest" more than you can afford to lose, that way when you lose (and you will) everyone won't have to hear you cry about it.

The smart way to look at this is as a bonus. Your money is gone, straight up. Deal with it, and look at whatever is coming back as a a good thing, not a shitty thing because it's taking a while. I mean, for fuck's sake, Arbs could pack it up and disappear any time he wants to. If I was him I can't say I'd still be paying back money to a group of people who cry every time I make a payment.