Puddle of Mudd singer Wes Scantlin is starting 2014 in debt ... because he allegedly didn't pay a hefty credit card bill and now he's being sued.
According to the docs -- obtained by TMZ -- Scantlin ran up $5,214 in AmEx charges within the last 4 years and has yet to pay up ... so now, the company's going after him in court.
A lot's happened to Scantlin since 2009, so the credit card charges could be for anything ... divorce bills, random luxury items bartered for cocaine, a buzz saw, you name it. But we're just guessing here.
American Express. Don't leave home without it ... but pay your bill.