PLEASE READ
If you went to the RLCS 7 World Championship, and are having any issues with the codes you're receiving/are supposed to receive, you must start a ticket with us on support.rocketleague.com. This is not something we can work through on Reddit. Thanks, everyone!
EDIT: ICYMI, these codes are redeemed in-game (Main Menu > Extras > Redeem Code), not through the platform you're playing on.