~Should it be right to start deregister them and put another email.
If you mean by "deregister" is changing the email. Yes, done that. Just a tip, you can pay great alternative email services like Protonmail[1] and Tutanota[2] like $1-$5 a month(depending on what service), and get multiple aliases to your emails. So you simply don't need to switch emails every time you want to check messages from other emails.
Or just like I write at the end of my post. you can use mail.com services. It's completely free, and you can get up to 10 aliases address in one email. The downside of this method is if the main email address that you use for login got compromised that means all of your email gone, so make sure that one email for login only for login and you never use it for something else.