iPhone unavailable screen, forgot passcode for screen

My screen is still locked on "iPhone is unavailable" with a time frame in which to try back again in 8-11 hours soon!! I also do not remember the passcode and the phone handset will not prompt me to reset it in the lower right corner as the help says it does. So please let me know when I can reset my passcode and the iPhone unavailable to progress in the activation of the phone.