Responsible for spouse's debt?

Got a call from a debt collector saying that my soon to be ex took a payday loan, didn't pay it and I'm named as the guarantor. Though I told them that I know nothing about the loan and never signed for it, they said that I'm responsible as of an e-signature. They are going to file a lawsuit against me. Am I responsible for a loan which I didn't sign? Can they come after my wages? What should I do?