A couple hours ago, I was within 30 thousand in rank, but after coming back on just now, I am withink 400 thousand! I haven't even been playing within this time to have gone down, so why did this happen! If so, could somebody please change my rank back to what it was.

Probably if you lost enough when you last time played, your elo went down, and it changed automaticly. Not really a problem

There's generally a pretty narrow ELO gap between ~25000's and ~100000's, so the chances are you likely just lost to someone with a much higher ranking than yourself.



Really though, rank is meaningless and if you're worried about it just win a couple games and your problem will be solved.