Tybox 827 rf shut-down?

I have a Tybox 827 rf which is not responding to my heating settings after I allowed the 'service due' reminder to go over the 30 days (ie the reminder had stopped flashing and become static) before removing it via the 'advanced configurations'. Do I need to return to the factory configuration then redo my programme settings? I think I do, but am nervous of messing things up. Or is there another way?