Reward Notification

I received a reward notification in the mail on 07.11.2017. When I went online to claim the reward, from starting service, it told me the notification was expired. how can a reward notification expire, when it was mailed on 07.08.2017 and not received until 07.11.2017. So it will expire the minute it is placed in the mail? Or if there was an online notification it was not sent to me via email to verify prior. How do I get the rewards that were promised when I signed up for this service 07.26.2017????