If you bothered paying any attention you would have noticed that on the top of the page on both the "Submit a Report" page and this Bug & Product Suggestions page there is a notice saying that Arena is having issues with a link you could follow for more details. And if you clicked that link (reposted here: https://magicthegatheringarena.statuspage.io/ ) you would see that the mail system has been disabled while they fix a bug with it and we will get the rewards later. Full notice here:
"Player Inbox Disabled
Identified - Due to issues with the @MTG_Arena player inbox, we are temporarily pausing our inbox messaging and rewards, including those for the 5th Anniversary. Once the issues are resolved, we will continue our messaging and rewards as planned.
Sep 25, 2023 - 20:12 UTC"

I never got an email in my account on September 27th for the 5th anniversay gift? What is up?

Still having this issue - is it still active?

Yes, if you bothered paying any attention you would have noticed that on the top of the page on both the "Submit a Report" page and this Bug & Product Suggestions page there is a notice saying that Arena is having issues with a link you could follow for more details. And if you clicked that link (reposted here: https://magicthegatheringarena.statuspage.io/ ) you would see that the mail system has been disabled while they fix a bug with it and we will get the rewards later. Full notice here:
"Player Inbox Disabled
Identified - Due to issues with the @MTG_Arena player inbox, we are temporarily pausing our inbox messaging and rewards, including those for the 5th Anniversary. Once the issues are resolved, we will continue our messaging and rewards as planned.
Sep 25, 2023 - 20:12 UTC"