Please report one of the messages that had this issue. You can report a message long pressing it and selecting Report Message. Please be sure to leave a description of the problem.
Please note that if you are not a Premium member then you will not be able to view messages that over 14 days old. To participate in Premium navigate to your profile and select "Premium" to sign up for the 3 month free trial. After the free trial you will be charged every 3 months (if selected) or annually, and the service will be automatically renewed. Your videos and photos will start to be saved at the date and time you start the Premium subscription (and cannot restore prior deleted videos).
You can also choose to save messages before they are deleted from our servers. To save a message, long-press on it and select "Save Video" or "Save Photo."