Hawk dlx engine problems

[Pharaoh]

Hey guys one of my friends helped me change the oil on my hawk DLX 250 2020 and he thought it was a great idea to put Castrol ATF in it. I believe it messed up the compression and my engine although I'm not entirely sure I need help figuring that out, but a mechanic told me I would need an engine rebuild kit. I'm trying to figure out the best website to buy that off of. I've changed the oil and bought a new spark plug. I bought the bike used with 80 miles on it I tried to take a trip to Chattanooga after the oil change and the bike shut off on me. it used to start and idle but would shut off after a certain RPMs now it won't start at all I'm trying to figure out what I need to do and the best and cheapest website to get it off of right now I'm financially unstable and that bike was my means of making money I need help today