I don't think it's bright doing business with financial institutions based in Cyprus , this situation as it were has been going on for many years now, yes even bright people get caught out , but not as often and not by firms based in places like Cyprus.
If you really have $750k on the line you can afford to fly your behind over to Isreal and hire either an attorney, a couple of big dudes, or both and compell the guy to turn over your money. If you're not willing to do that then it would seem to indicate you simply don't care that much.
your advice is useless. you don't even know where these Israelis are located assuming that there is an iota of truth to the OP losing 750K. furthermore you will not be even able to determine who the identity of the individual Israelis involved.
Sounds easy enough , but this won't be their first rodeo ( as they say in the states) , the money is already being spent on coke and girls, people don't get their money back from businesses that are legitimate and go bust , let alone from scam businesses. Long gone is the expression I would use.
Assuming the story is true, OP never said how much he started the account with. Maybe it was only 100K*. Or maybe it was 2 MM, so he already lost the bigger part of it while trading. *He may have to pay taxes on stolen money, a double fuck as my nanny would say
You are a sucker for binary options. Please Google all about them and you will see the "honest" firms take too much vigorish so you will not win in the long run unless you are Michel de Nostredame usually referred to as Nostradamus. If that is who you are, there are better ways. Seriously... you have a blind spot and reading 100 Google articles and posts may help.