Sorry to hear your unit is not working.
Pending Anker responding, have you tried the 'ole technique of trying every possible sequence of pressing every button with and without the power cord in? Sometimes it works.
Sometimes infinite monkeys works.
BTW my work supplied laptop will not power on til I plug in the power cord, then it can run on batteries. This relates to POST. Power On Self Test. You unit could just be confused a bit of Random Monkey can fix.