I asked the client to give me a 768 video, still gives me a 510, then rants that the video on their site is blown up and the people's head are cut off... WTF

a brief email clearly stating all the deviations you have taken due to them not giving you what you wanted. weekly. and when they bring that up, just show the emails to them. Everytime they bring this up, point to email. eventually most realise their mistake. most people. the others, take extra steps to never ever work with them again.