This is a collections scam.  They claim you owe a debt that you don't and that unless you call 888-792-2348 number right away, they are going to have you legally served at your place of employment.  Complaints have been filed with the U.S. government against them and their number checks out to some U.P.S. store.  Total scam.  If they call you, tell them immediately that if they call you again, you will have them arrested for harassment and hang up.