Kocaso M830 - Power Drain Issue

[Leftie]

I'm afraid I can't seem to find the new topic creation button... anyway, I recently bought a Kocaso M830, and I'm having a power drain issue when it's off. I charge the battery completely (and did when I first got it) but after a week turned off it's critically low again. I have WiFi off. Anyone know what's going on here...?