NOW internet Billing

I am looking for help to get a refund for my NOW Internet charge. NOW Internet charged me for full month. I cancelled 1 day after the charge. There is NO single person or department that can help me with this refund. I have been calling XFINITY for the last three weeks. AI chat cannot help since I do not have the account now. And there is no department XFINITY can connect me to get my refund.