I am an non exempt employee and worked over time. Have exactly 240 hours of comp. overtime and they are requiring me to take time off rather then pay?

Employers are required to pay non-exempt employees for all overtime (hours over 40 in a workweek) during the pay period in which the hours were worked (with a few execptions). Time off in lieu of paying overtime is not allowed unless you are working for a governmental employer.  Set a consulation with an experienced employment attorney as soon as possible.