On July 21, I lost 75% of programming

New mini boxes installed on two TV sets a few weeks ago. Haven't had any problems... until last night. Lost most programming on only one TV. Each unavailable channel was marked "Unavailable Program". Unplugged both mini box and set for a couple of hours. Turned it back on and got bit-mapping on most of the unavailable channels. Turned it off. Just turned it on again after about 5 hours, green light on mini box is blinking off/on, and the screen is only showing the Cox logo with 6 boxes (3 are yellow, 2 are green and 1 is lavender). What now?