dude that's ur account
Imitators
Reported both - i ran into them a few times yesterday already and thought it was strange you would do this - although they largely resigned the games before starting

Thanks DontKno. Those accounts are banned now. And I don't think there are any more plausible ways to imitate my username by using lower case letters.

It's the upper case "I", not lower. This is a weird "feature" of the standard character set used by many computers, upper case I and lower case L display exactly the same. Chess.com stores user names case sensitive but searches case insensitive, so you can bring up the fake guy's account with this:
https://www.chess.com/member/jarIcarlander
which looks like all lower case letters but the "l" in jarl's name is actually a capital I.
Someone is impersonating me, simulling in bughouse.
https://www.chess.com/member/jaricarlander
https://www.chess.com/member/jarlcariander
I don't know who it is, or why they are doing that.