I selected the add-on when I upgraded using the website.
Now, when I text PRIME VIDEO to 150, I receive a reply with the expiry date.
Amazon prime is only available via EE swappable benefit or by paying monthly for the service.
There is no longer any free trial.
I don't have Swappable Benefits, but I claimed the 6 months free whilst the offer was still valid. It is now showing as one of my add-ons, but it was never set up.