@Lando, the cheating in no way impacted your games.
@everyone who's curious, Multi means someone with more then 1 account. Not all multi accounters join games with their other accounts. Some people make an account for gunboats and an account for full press, some to take over cd countries, some to point mine, some to talk to themselves, etc. It doesn't matter why someone has multiple accounts, it is not allowed. This person was banned for being a multi accounter and rejoined, and was hence banned again.
@Nigee, quite a few people are given second chances, when this happens the mod team does not simply unban them, we watch their account and make sure they don't cheat in the future, but as abge mentioned, the specifics are no one's concern. Just know that many people who are given second chances end up becoming well known members who contribute positively to the community.