Chuwi Hi9 Air Tablet

I have a problem with my Chuwi Tablet Hi9 Air.

Anytime I just press the power button, the tablet goes completely off and it will need a very long press to come on. Also, once the screen goes off, the tablet goes completely off. I need to keep the screen on to keep the tablet on. This is really a big problem.

Please what can I do to stop the problem?