can they take all your money and leave you no mone

You haven't mentioned whom you're speaking off. Are your speaking about collection agencies? You should note that in order to collect the debts from you, the collection agency has to own your debt account. They can garnish your bank account only when they receive a judgment from the court. If a collection agency is illegally debiting money from your account, then you can close your bank account and open a new account with some other bank.

You can get detailed answers to your query from the following page:

"http://www.fair-debt-collection.com/searches/garnishment.html#bank"

If your bank account is being levied, there's a judgment against you. Were you never notified?