Looks like Ive been a victim of exactly the same thing Justrugby.
Ive got lucky though I guess as I am about £3000 down from the initial deposits.
My balance is $12500 but S1 have taken it all for the IPO on FLY.
They are now refusing to refund it.
I will also try with Monzo but they wont do anything.
ITS A SCAM folks !