Flip screen display won't rotate 180 degrees

I recently bought an a5100 from MPB.com listed as "well used" in terms of condition. Within the first day of use, the camera seems to function perfectly (save for some dust in the sensor that I can easily clean) except for a detail that is quite important to me. I bought the a5100 because of the flip-up screen as I intend to use the camera for vlogging; however, when I flip the screen up to face the front, the display does not rotate and the preview is upside down. I really would like to avoid the hassle of returning the camera (as it does have a 6 month warranty courtesy of the seller) and want to know if there's a simple fix I could try to get the screen to rotate. I have already tried factory resetting the camera and it did not fix the issue.