To view the details of a reward, navigate to the History section and click on the individual reward. (If you need assistance in locating a specific reward, here is an article describing how to search through your reward history.)
Clicking on an individual reward will display a details panel that includes delivery status along with the associated metadata.
Kindly note that Tremendous reports only delivery status, not redemption status. Recipients have three years to redeem their reward, and cancellations are reserved for qualifying rewards that were sent in error.