Due to a known issue, when an event ends, you may not see on your screen the reward details pop-up that normally appears and lists all the obtained end-of-event rewards. Especially if you have recovered your Cloud Save using a social account (Facebook, Google Play Games or Game Center).
Rest assured that these rewards have been directly added to your inventory as your profile is stored safely on our servers. This is how we are able to confirm that you have received the content of these event rewards.
This is what we call a "display issue", this occurs when the game displays incorrect information or doesn't display all the information you were supposed to receive on their screen.
We thank you for your understanding and apologise for the inconvenience caused.