I have upgraded my Mobile plan and xFinity is charging a wrong bill, according to the old plan. And the Chat Assistant is useless

I have been a customer of xFinity for 9 years however now I am definitely frustrated. I upgraded my plan in April 2026 and now I got a bill that refers to my old plan. Attempted to get some idea on what is going on via the Chat assistant however this Chat assistant is completely useless. The standard options available on the Chat were designed by someone who has no idea of customer needs. It gets on and on a loop and go nowhere despite trying all possible alternatives. In the era of Artificial Intelligence, the Chat bot is a complete failure.  It is impossible to speak with a real person and explain the problem. I will try solving this by going to a store, which is such a waste of time.