Help getting started with Roku devices, including setup, connecting your device to your TV, linking a Roku device to your account at my.roku.com/link, adding channels, subscribing to services, and more.
Activation code for what channel or service? If you're activating a roku device you don't receive it by email, it would be on screen.
If it is premiere device itself, I would do a factory reset, with it powered look for pinhole in the back of the device, insert something and depress for at least 50 seconds. After it comes back, set language, and internet, enter the roku.com/link in your computer or cellphone browser address bar, NEVER enter it into a search engine like google!!!
I changed my roku account email from ...@cox.net to ...@gmail.com. With @cox.net it took 3 hours for the email to arrive, @Gmail took seconds. I guess cox is slowing down emails from roku now that they are also offering streaming devices.