How to see if your client exists on Companion
Click on your profile icon and in the dropdown select Clients
You will be redirected to a new page. Sort the client list alphabetically if it helps! Look for the brand name within the list and click Users. This is a list of all your client users i.e. those who have access to Companion. Here you can edit user detail, reset password, assign permissions (what campaigns they have access to) and delete the user.