Dear Ubi-Bunny's Final Announcement is as follows:

"Compensation Update - June 30th

We have just rolled out the inbox messages for all players who did not receive their Leaderboard rewards from our recent Helix Rift Event, THE OTTOMAN CONNECTION.

Once again, our sincerest apologies for this issue!
"


SOURCE: https://forums.ubisoft.com/showthrea...1#post15465664

NOTE: If you haven't received a message in your Inbox yet, try resetting the game and check your inbox again.