Mobile service and billing

Have any of you had this problem? I Did xfinity mobile incentive 2 years ago and left Verizon. Big mistake. Switched back almost immediately but left my dad's service there because he did not need international coverage and he really doesn't use the phone.  I wanted him to have it for emergencies. Dad dies beginning of February 2025. Try to cancel online when I discover that they have been billing me for 2 phone lines instead of 1. My daughter's line was switched to Verizon almost 2 years ago after days on the phone with xfinity [Edited: "Inflammatory"] people.
Takes me forever to talk with a live person on February 11 because I want a refund for the 2 years of charges for the second line and ensure that my Dad’s line is cancelled. Finally get a live person and he agrees to cancel both lines and give me 1 months refund. Get emails confirming cancellation but no refund. Guess what, billed the next month for 2 lines. Call American Express to dispute it and ask about refund. They are working on it and ask me to call xfinity also. I terminate direct pay as recommended by AmEx. I dread that call and procrastinate. Oh guess what another bill from xfinity for 2 lines. So I try to contact them again yesterday. Takes me 20 min to find a number that actually gives me a live person. Unfortunately it is someone with such a thick foreign accent I can't understand 90% of what he says. Ask for a manager. Nope refuses to get one. And will not honor the deal that the person I talked to in February.  In fact, according to him I must pay the 1st bill, no refund. I am going to let Amex take care of it. [Edited: "Solicitation"] Has anyone else had this kind of billing cancellation problem?