eleaf Istick qc200W. random shutdown issue

Hi I have a I have a eleaf Istick qc200W. for past 2 days its behaving weird its shutting down automatically inspite of having enough battery power i have never dropped it nor it has been mishandled please tell me what to do?

Please check this video

https://www.dropbox.com/s/z3q9svf1650l9y...