In the old system it was possible to have 3 subscriptions in 1 account. After migrating to the new system each subscription has his own account. That’s why you receive 3 separate invoices. Since each of the 3 accounts have the same username (copied from the old system) only the first account in the database will be shown after you login. Change the username of 2 accounts so all 3 accounts will each have a different username. To do this just login and change the username of the account being shown. Logout and login with the old username again (you will see another subscription) and change the username of that account also.

Now you will have 3 accounts, (1) account with username changed first, (2) account with username changed secondly and (3) account with still the old username Now you can access them all separately in Mijn Tele2. In the app just login to 1 account and then add the others by pressing the button in the left upper corner of the mail screen.

Unfortunately there is one catch, every username should be a valid email address, so you will need 3 email addresses or aliases. I’m not sure if the customer service can transfer all 3 subscriptions to just 1 account again.