Q 1 E-mail sent a message saying that the account was logged in by someone else. Can clicking on the link be true?

This is not necessarily true. Log in to your QQ first to see if the mobile phone number is really bound. If it hasn't changed, then this email is stolen. Don't enter any account and password in this email. If it is bound. Just forbid QQ login. If the QQ security center is bound, you can use it to exchange the secret mobile phone.