Deleted Mail with Challenge Rift Reward in Diablo III

When you complete the Challenge Rift in Diablo III within the time limit, you will receive a reward in the mail on the next character you log in.  If you delete the mail without getting the reward from it, or if the reward mail expires after 30 days, Game Masters cannot restore this reward.  You can try completing the Challenge Rift again, but you can only receive this reward once a week.  You may need to wait until the following week, and try the new Challenge Rift.