First, check your Inbox -> Notifications. Click claim in the notice. Please do it promptly because the notice will expire after 30 days, preventing you from claiming the rewards.
If you did not receive your reward, the reason might be because your friend did not log in with a new device or a new ID. Both a new ID as well as a new device are necessary for the system to determine if your invitation was successful.If you did not make any mistakes in the process, please send both you and your friend’s User ID and User Name to firstname.lastname@example.org. We will tend to it as soon as possible.