Norton Mobile Security - Not able to use my available device slot

Hi,

I have Norton subscription which can cover 3 devices. I have added two devices (1-desktop and 1-laptop). Now I want to add a Mobile to it. I have added a device and I got a link on mobile. Using the link, I am able to install the Mobile security app on my Android phone (Nokia 8).  But it shows only 30 days trial period. I have waited for 30 days and want to update the details. It is not allowing me to do that. On Mobile from Google play it is showing a charge. Since I have a slot available, I want to utilise this and do not want to buy a new subscription.  Please advise me on how to set this up.

See my screen shot of my available device slots.

Please advise.

Thanks

[Admin Edit: Removed screenshot with personal email address]