Looks like you're in touch with a member of our User Support team via email to help you get logged back into your account. I would recommend following up to the last email you received.
Device Activation + Codes:
If you're attempting to activate Pandora on your mobile device, you already have simply by signing into the app with your Pandora account email address and password.
The Device Activation tab is for activating your Pandora account on in-home devices such as Smart TVs, Blu-ray players, etc. These devices generate codes that need to be entered on a separate device for activation.
You can activate a device using the Pandora app:
Open the Pandora app and go to Settings, then tap Device Activation and enter the code.
Then select Continue on the in-home device.
Let me know if you have any trouble activating a specific device. 🎧