Thank you, @renojim . That makes sense and I had not done that. I completely logged out of Roku after deleting the Peacock app and restarted accessing “settings>system.” as you suggested. The result, however, was the same. The only option was to start a new subscription via Roku. There was no option to log in/link and existing subscription.
@jojobird, well darn. I was hoping that was it. If I start Peacock I get an option to "Get started" or "Sign in". I assume you get something different?
You can try going to https://support.roku.com/contactus and choose the option for "Account, payments & subscriptions" and see if you can get to a person that can help. It seems as though once you have a Roku subscription there's no way to get it to forget it.
Did you ever find a solution? I’m having the exact same problem with the Peacock TV channel.