This TV does not support any video format. That is what the manual says. The USB only support jpeg pictures in FAT file system. A similar analogy is when you buy a computer that is able to read a DVD but not write to it. There many that can write to a DVD but the one that you bought cannot. There is nothing wrong with the TV.

If you want to play videos from a USB drive then you need a different TV that specifies that it is able to do it. You also need to check which video format is able to play. The fact that it can play some video files does not mean that it will play all videos.

A cheaper solution is to buy a media player which has a wide range of formats that can play. You could see an example of a media player at this website http://www.ebuyer.com/274064-cyclone-micro-2-mkv-player-cyclone-micro-2-player . This can be connected to the TV via HDMI.

I hope that this will help