Shipmondo allows you to have one email address linked to multiple Shipmondo accounts as staff members.
This requires that the email address in question is not already in use as a main company account mail at Shipmondo.
You can see which account/company you're logged into if you look at the upper right corner of your Shipmodno account.
If you have access to multiple Shipmondo accounts and wish to switch between them, start by logging out of the current account and log in again.
At login you'll be prompted to choose which Shipmondo account you wish to log into.