When you deposit money with the bank, it becomes the bank's money, as a matter of law.
Obviously, it behooves them to honor your request to withdraw funds, but there is a reason for the FDIC apparatus. If a bank is unable to return your deposit (the bank goes insolvent), you do NOT have a cause of action against the bank, to "get your money back."
Mattresses will rise again! I say, I say the Mattresses will rise again!