The Federal law limits wage garnishments to only 25% of your disposable income.
They can't garnish your whole wages and have to leave you some money for living expenses etc.
You can also stop a wage garnishment by going to a court hearing and filing for Chapter 7 or Chapter 13 bankruptcy.
Usually when you're 6 months past due on debts the creditor will sue you in court and try to collect by garnishing wages.
You should always show up for court otherwise the judge will rule in the creditors favor automatically.