account garnishmet

I siged for an automobile loan for a relative in 2001 the person stopped paying on the $2,800 balance in 2009 I received a subpoena stating that I was being sued for the balance. I contacted the creditor and scheduled a payment plan with them and made payments until I became unemployeed. I would still send payments but I missed 2 months. When I did send a payment they sent it back stating that they were going to execute on the judgement. The next day after I received the letter my checking account was debited and negative 2,700. My bank is not going to pay it and any checks that I have out will bounce. Do they have a legal right to garnish my checking account when a judement was never signed by a juge and the legal amount in my state to garnish a check is 25%?