My name is ***** ***** certified professional with over 10 years experience. I will be glad to assist you with this.
I am sorry to hear that you are having this issue.
Check in your Settings, then go to Messages, then look to see if there is a setting for how long to keep the messages. Let me know what it is set on please?
do you still need help with this?
okay, this may be your messages being stored. It could also be your videos and pictures. Do you have iTunes software installed on your computer?
okay, if you have iTunes on your computer we can use the iTunes program to find out and correct the problem with the iPhone.