@RJones,
It's not a new account creation, look, for example If you add my e-mail as an administrator in your organization It will be showed on my MSP portal, but my e-mail is an existent account on Meraki dashboard, so maybe someone did It using your e-mail, but maybe It was a mistake.
You got It?
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
Please, if this post was useful, leave your kudos and mark it as solved.