Peacock upgrade to Premium Plus while Xfinity pays for Premium?

How can I upgrade Peacock Premium Plus if Xfinity is paying for Peacock Premium free from the rewards program.

Peacock doesn't show on my account under app and subscription and I've call and talk to a few people at Xfinity they took screen shots of the TV that its doesn't show listed but I have access.

But can find a way to upgrade, I was then told if Xfinity was paying for the Premium than I can just do the 4.99 to get ad free I would need to make a new account and paid full.

Can't use peacock website or app says manage by xfinity and all changes must be by them, but it doesn't show on my account where I can see or make changes.

Thanks for any help or info.