Lookig for repaire solution or place

Hello,
I bough one of that TV box from Kijiji
It did work for a month and now is dead.
The seller is a jerk and does not want to fix it or exchange
He is in Toronto Markham. His phone number is 647-692-6547
Stay away from him
As new user I cannot post the link or picture
OTT TV BOX model CS918S
Beside the point, I would like to find a way to see if the box is dead or not
I plugged the RJ45 cable on it and my router but no activity lights on router port
I plugged the HDMI cable on TV, but nothing on the screen
It has a USB port.
Can I connect it to my PC and check it from there ?
What software to use ?
Please help
Thanks