How to fix video shot vertically on a smartphone?
VLC Media player, which is free, allows under it's Tools -> Effects and Filters a Geometry Tab, which you could try for rotation. 

Then you could use the Encode/Stream option under File - to try to get a decent output. 

However, unless your camera has some sort of ccd/cmos rotation feature, if the video was shot vertically, you shot it using only a fraction of the sensor, discarding the vertical space on the top and bottom to create a letter box version at a lower resolution. 

You can up-res it, either simply, or with an expensive plugin, but it's never going to be "full resolution" because the information simply isn't there.