Quicktime videos giving "We were unable to open the files on disk" when importing from hard drive

I'm a PC user creating videos for my internship. All the videos I am tasked with editing are recrorded on iPhones and uploaded to a server via Mac finders. Since I don't have access to the server, i've been using a hard drive to get these video files from my coworkers. I'm having so much trouble using iPhone videos in the newest version of Premiere (24.4.1) . After downloading the video files to my hardrive, none of them are able to be opened in Premiere. I can't open any of them in media player either. I've tried cleaning the media cache, I've tried converters, I've tried changing the file locations. I'm starting to think this is simply a compatibility issue between Apple and Windows. Please help this has made working impossible!!!