This is usually a phishing scam. If someone can convince you to change your primary Instagram email address to something they control, then they can completely take over your Instagram account, and you won’t get it back. Always verify that you have control over an email account before making this change.

Some Instagram accounts routinely switch back and forth from private to public and back again because it is an easy way to automatically accept follow requests. When you switch from private to public, all requests are approved and stay that way when you switch back. This allows private accounts to have large following.

If you delete a picture that you posted to Instagram, the picture will no longer be visible to other users on the platform. But, any screenshots or copies of the photo that were made will still exist after you delete the post. On top of that, the post might be archived, and you would have to ask to have it removed.

If the request is canceled before the other person checks their account, they should not know that anything happened, and they should not see a request. If they have push notifications to their phone, they might see a notification even if they cancel. If you’re slow, they’ll see the request and know everything.

Typically speaking, they will get a notification about a missed call. This notification will tell them who called, when they called, and that the call never actually connected. In some circumstances, you might be able to disconnect before the server processes the call, in which case they won’t get a notification.

This happens because the account has low levels of engagement from its user base. This can happen when the user base is largely made of bot accounts, when the account owner doesn’t post often, or for a large number of other reasons. It boils down to a disconnect between getting followers and engaging with them.