The most likely reason is that your ex wife lied and told the creditor that you were guarantying the loan or that you were still married, in order to look like she was a better credit risk. Contact the creditor or collection agency, explain the situation, and provide evidence that you were not married at the time of the loan (and ask why you are being garnished under this situation)--that may resolve the situation amicably, once they realize you are not legally liable. If it does not, you can file a legal action in court to get the garnishment eliminated and recover the garnished money. You local county court clerk can explain how to do this.