You may have created or have been invited to multiple company accounts in Envoice.
To switch between accounts you have to click on your profile button on the top right corner.
If you are a user in less than 10 company accounts, you can select an account from the dropdown list.
If you are a user in more than 10 company accounts only the first 10 accounts are visible on the dropdown. To see the rest of the company accounts click Show more.. button. On the new window, you may use search functionality or just scroll and select an account from the list.