max boox carta won't turn on

hi this is benyamin mohamadalizadeh
i bought a max boox carta 04 May, 2017

i was happy with my boox till last night that it suddenly stuck on “power off” screen and wont turn on …
i try everything power+back buttons for 10 second , not work either .
plz help …

Please charge the device with the 5V 2.4 A charger for several hours and then follow the following steps to restore the factory default settings:
Please try to restore the factory default settings as following steps: Switch off the device firstly, and then long press back + power buttons, enter into recovery mode, to choose “wipe data\factory reset – yes delete all user data - reboot” to restore factory default. This will delete the personal data (such as reading history, applications, some personal setting) but won’t delete those files in storage.

*Please notice that all the personal data will be deleted after restoring the factory default, including the personal files.

If that has not fixed the problem, please fill in the Service Request Form carefully, and we will reply back as soon as possible.