Obtaining video footage for case study

Recently a client produced videos for a case study and uploaded it to Google drive. The videos are typically 20 minutes to an hour long and in .mp4 format. The video and audio plays fine in Google drive but when I download the videos do not play right or are without audio. The client was not able to upload the videos to a free Dropbox account which I am not sure if Dropbox would even work. The last resort I have thought of is to send a thumb drive to the client so he can put the videos on there and send back to me.

Does anyone have experience with transferring video or have recommendations?