Like with any potentially compromised account, the most ideal means to prevent further damage is to simply change the log-in information associated with it. More often than not, this will throw a potential hacker off and ensure account security for the foreseeable future.
With regard to the Instagram situation, in particular, it might be a little harder to handle. Considering the emails are being sent because of a person’s username, the only real way to avoid that is to change your username.
If changing your username isn’t a dealbreaker, then that will almost assuredly stop the spam of emails. However, until Instagram changes the rules that password recovery emails need more than just a username to send out, there isn’t much else that can be done to secure your account.
Of course, when and if Instagram decides to change those rules, we’ll be sure to update and include that information as well.
View more information: https://www.distractify.com/p/instagram-trouble-logging-in-email