Why did I end up in a blank tenant after accepting a Push admin team invitation?
If you ended up in a fresh Push tenant after accepting an email invitation, verify that you are using the same email address that was linked to the invitation.
If you are using a variation of that email address, or a different domain, you will not be automatically joined to the same tenant that your colleague invited you to.
To fix the issue, sign up using the same email address. You can then safely delete the account linked to your alternate email address.