Try log out from WBID in MKX and quit game, then relogin, try change Factions, try unlink account on wbplay and link again. If nothing helps - try WB support, link in my second post.
I've got their reply habibi
Thank you for contacting Warner Brothers technical support. We are sorry to hear that you didn't receive your reward.
Please note that it may take up to 48 hours after a multiplayer season ends before rewards will be granted to players who participated. This process allows the developers to calculate rewards and make sure everyone receives the reward that they should have.
If you still have not received your season rewards 48 hours after a season ends, please log off and back in to your WBID account in the game.
If the issue persists, please submit a bug report at support.wbgames.com by clicking Ask for Help and selecting Bug Report as your Question Type. The developers will then be able to investigate your report.
Please note that we at Technical Support do not have the ability to grant season rewards retroactively.
Thank you,
Paola.M
WB Games Support
I should wait it out I guess
btw, thanks habibi for the link