If the a Pet Event ends during a battle, your rewards will be mailed to you. However, if the Event ends during the 8th Battle you will not lose the Pet Reward.
All baskets or stage rewards for battles fought will be sent in the mail (such as Jewels, Pet Food and gold). The Pet you are trying to rescue will not be awarded unless the final battle is completed before the Event is over.
If you still believe you are missing rewards, please contact support with "Missing Rewards" selected. We will check the logs of your account to see what went wrong.