We are community members, so cannot help with account problems, password lockouts, or 2FA issues or even email delivery because we are not administrators of gitlab.com. Searching the forum would give you many posts where people have had the same problem, and the reply is open a ticket. The link below automatically has selected the Gitlab SAAS User account and login issues problems option.
https://support.gitlab.com/hc/en-us/requests/new?ticket_form_id=360000803379
if you are using your own server and not gitlab.com then I suggest ensuring that you have configured gitlab so that email delivery works properly.