hey, i tried requesting this as a new category and mods refused it as they say "you need to submit your own run" nothing says that in the rules

From the second paragraph on the game request page:

"For your request, we require a video of a full-game run played by you. We strongly prefer such a run is not a segmented run, and may reject requests if they are segmented runs. If a game is heavily based on Individual Levels and does not really feature a full-game run, a playlist of an overwhelming majority of the IL's for the game is acceptable. Submissions which do not meet this criteria will be rejected without being considered."

well i sent a video of a full game run played by me and it was on an old youtube account of mine but i forgot the email and password but i did link the video and it was not just segments so why would they decline?

Did you explain to them that the video in question was from an old account of yours? If not, I would guess that they assumed it was someone else's run, as there is no reasonable way for them to just know that it was your old account.

You could try to resubmit the request explaining that the video is from an old account of yours, though I'm not sure that will be enough, as it might be hard to prove. Your best option would be to record a new run and use that for your game request.