Xfinity created a new account when I changed my internet plan

My 1 year contract term with discount rate was set to end this upcoming February so I decided to proactively signed up for a new plan instead of potentially forgetting and being charged a much higher bill. I was logged in my current account, but somehow during the process Xfinity ended up creating a new account for my same address. My old plan looks to still be intact on my original account and it looks like I will now get double billed. How can I have the new plan replace the plan in my original account? How do I make sure I won't get double billed? Also, I want to continue using my original account since it has all my order and payment history.