Indicate charging while its unplugged!

Last 2 days ago I connect charger to charge tablet ( it was 70%) then after an hour checked again and whoa! 30%!!!!!! Check battery usage and noticed although I connected charger cable but battery drained inverse!

Unplugged it and try another Asus 7 charger and same problem, Battery goes off after 0% and when I plugged again just flicker screen and nothing happend, I tried cleaning USB port, changing cable and charger and done instruction of nexus Google website ( Press power + volume and bluh bluh bluh) even remove battery and charge it separately with power supply then put it back again, tablet switch on again and andrid comes healthy but again it shows charging!!!! no charger and indicate charging!!! I even flashed the whole rom and boot loader, doesnt solved,

I dont know what to do,,, Battery is healthy charger is healthy , usb port is cleaned but problem insist

What do you suggest?