Hey guys ima show you how to secure an instagram step by step
1. once you gain access go to edit profile tab
2. change the password and save changes
3. change the email address
4. see if you can share a picture with facebook(if so ask for the facebook login and secure the facebook aswell)
5. if there isn't a facebook linked to the profile make a fake one to link it with
This tutorial if followed correctly will make it impossible to access the instagram(unless you tiger).