Cancellation refund

I cancelled service with Xfinity on March 3rd, 2023, but was subsequently billed another full monthly billing cycle (~$285) and then only refunded ~$12. I've attempted to contact Customer Support on at least five separate occasions to get this resolved. In speaking with them, they admitted that Xfinity made an error in processing my cancellation which caused an incorrect additional bill, and promised that someone would contact me with a correct accounting. Unfortunately, despite numerous promises I have yet to receive ANY response from the refund/billing team.

I request that someone from Xfinity actually respond to me providing a written calculation of my fill pro-rated charges and appropriate refund. Unfortunately, absent this my next step will need to be disputing the charges on my credit card, following which Xfinity will be welcome to discuss with my lawyer.