That may be a Sprint thing. I know they were sued a few years ago for over charging a bunch people on minutes. I had a spint phone a year or 2 before this happened and I remember they jacked my bill up like $125 and I never went over my minutes. I paid it like an idoit not knowing what to do.
their reporting is messed up or something. Thay proably sent an illlegitmate debt over to a collection agency. Dont pay it the last perosn was right it will reastablish the debt, just send a letter disputing it to IC Systems. They will send it back over to Sprint and Sprint will be required to send you an explanation of the debt, send Sprint a letter to.