All functions vanished from watch

I performed an app upgrade on my watch using bt notification apk as recommended by the instructions. When I went to use my watch all of the functions have disappeared. I can't perform a factory reset as this was in settings, which I cannot access. The watch face screen is visible but showing the wrong time, which obviously I can't set.

I took it to a watch mender, who can't fix it, I took it to a mobile phone repairer, just on the off chance but they can't fix it either.

Can someone please help?