Cancellation Request not Processed and no Notice of Recurring Charges

I moved before the end September. Before my move, I made sure to contact Xfinity support to cancel my service through the buried menu option in my online portal. A few days later, I received a call confirming the details of my cancellation request and a promise that I would only be charged until my last day of service for my last billing period. I also received a confirmation email again confirming these details.

Since I have no equipment to return, my move date comes and goes. Then lo and behold, I receive an automatic billing notice stating that I paid the full balance. Even though my cancellation date is over two weeks before the end of the billing period, I'm paying the full bill, no proration whatsoever.

I message Xfinity support through the assistant and get connected with an agent. The agent checks on my account status. Turns out the cancellation request was recorded incorrectly over two weeks after my requested date. Turns my account is still active and accruing charges with no notifications that Xfinity failed to adjust the status of my account.

How can I go about resolving this immediately?