Of all the agencies I have used over the years there are only two that I know of that demand cash up front from the airline, I.E they are paid 1mth in advance.
This way if they don't get paid they have at least 1 mths salary in the kitty and you are going to have your last months salary if it all goes tits up, obviously with no notice, unless you want to work unpaid for a month.
Both of these agencies have names beginning with P,
1 is in Ireland, the other in Switzerland.
AFAIK none of the others offer this "peace of mind", and I have been let down by 2 others who would no doubt call themselves "major pilot agency" Bla bla bla
