I bought this pre owned tv and the people forgot to unlink my device. How do I make it link to my new roku account without using their information and email?
You created a Roku account in order to post here. You can use that.
Log in to your Roku account: https://my.roku.com/
Next, on your Roku, do a Factory Reset.
Settings > System > Advanced system settings > Factory reset
You'll be presented with a 4-digit code, and will have to enter it to do the reset.
Once the reset completes, it will be the same as setting up a new Roku.