Bad news: It's legal for a creditor with a court judgment against you to freeze or "attach" your bank account. Some creditors, like the IRS, can attach your account even without a court judgment. (Learn how to avoid frozen bank accounts.)
But there are limits to what the creditor can take from your account. If all or some of the money came from sources such as Social Security or a public assistance program, this money would be protected. To prove that you deserve this protection, however, you'll have to ask for a hearing.
How to request a hearing, and how soon you must request it—usually pretty soon—varies from state to state. The best way to start is to ask the bank for copies of all the attachment papers. These papers might explain the court procedures for claiming any exemptions from a freeze and getting your money released. You should also consider hiring a lawyer to help you. If you can't afford an attorney, call your local legal aid office for advice and possibly low-cost legal representation.