During the activation process and in many places in the account web pages show the username as being the same as the email address. It was clarified by @Mary_M that if the username is changed after activation, the email address does not change and that a request to a moderator is needed to revise the email address. Please revise the information in the account web pages to this effect. Alternatively, make changes so that when a username is changed, the email address changes also so that the two remain the same all the time. Keeping the username and email address the same all the time is preferred as this means one less thing to keep track of.