Hello @TomO1129 ,
If you have access to the account owner's email address inbox, it'll make the process much easier. You can utilize that to reset the owner's MFA method via the login screen, go through the forgotten username/password processes, and update the account info.
If you cannot access the account owner's main email address, or you're unable to reset the MFA method from the login screen, then you'd need to call in for account security protocols. Once account security questions are confirmed live with the phone agent, they'll be able to assist further with resetting the MFA, updating account info, etc.
See also:
Transferring Constant Contact account ownership
MFA FAQ
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