AFTER closing cellular account with Sprint, with zero balance due, contract ended a year ago -- and Sprint through IC Systems wants $189 -- but neither can provide any proof that the charges are valid (other than they say so) or even what they are. "Final bill" is all they can/will say. When disputed in writing to protect my legal rights, the calls from IC Systems increase in frequency, rudeness and violence. IC's Manager that jumps-in mid-call is a blustery bully and useless in getting any real information that might backup and validate their claim.