Hi Jimmy,
Try logging into the Meraki Dashboard, and clicking your name on upper right corner, and update your email from there. You should be able to change it from user@domain.com to whatever you want, and those permissions will carry throughout all organizations.
That is one nice feature of Meraki -- let's say you fire someone and need to change the password. Once you change the PW for that account, access to ALL networks have been updated. That is because that account is granted access to each account.
When we onboard a new Meraki customer, we grant access to our general MSP account, and then myself and another high level tech specifically.