how to reset my chess elo?


You don't have to reset it. It happens automatically.
Your play has caused your blitz rating to drop by 145 points. I'm sure that feels uncomfortable but it's really not that huge of a change and should change the level of opponents you face.

Every game I play my ELO goes lower and lower. I don't know if I suck at chess or play a bunch of cheater but I'm in the 400 range.

Every game I play my ELO goes lower and lower. I don't know if I suck at chess or play a bunch of cheater but I'm in the 400 range.
There are millions of players in that range. It looks like you set you initial rating way too high and it has taken you a while to get down to 400.
You should keep playing. You will soon find the rating level where you win about half of your games.