This guy is correct, and is so with delightful flavor I might add.
They will be locked in a security trust and managed by the hutts.
You will have no access to your money above the verge of 350.000 credits for preferred players. There are cartel items allowing your to withdraw credits from this trust.
The moment you subscribe again, the hutts reluctantly give you back your money and kill a wookiee (win-win situation!)
Subscribers who unsubscribe get moved down to 'preferred' status. I believe your cap at that point will be 350K. Every other credit that you have, and that you earn while capped, is put into 'escrow'. You can purchase the ability to withdraw credits from escrow. Also, if you resubscribe, access to these credits are restored.
I know this is annoying, but this is actually a design decision that was made primarily to slow down credit farmers using free accounts to abuse the game. We are continually examining things like this to see if we can lessen these sorts of restrictions on players without creating a haven for credit farmers.