Device promotion not applied and being charged full amount, please help!

I called on May 2nd, 2025 to set up my newly bought home internet box. The agent, after helping setup my device sold me on a free limited line promotion and promised a device discount promotion on top. I did the math multiple times over the phone as I never want to pay MSRP for a phone as they are always discounted. Anyway for 2 hours we were on a call and he kept confirming that my phone would end up costing somewhere near $700 when its all set and done. So I foolishly believed the xfinity customer service agent and I bought a phone from Xfinity on with the free unlimited line promotion and there was supposed to be a device promotion applied as well (for the Samsung S25 ultra). They mentioned the discount would be reflected monthly in the bill instead of a single discount on one payment, But that agent did not apply the promotion it and since then I am getting charged double for the device ($50 instead of around $30)! This will make the device cost $1400 instead of around $700! I already paid $78 (50 for device, 25 activation) for the second bill (after the initial $266 in "fees") and I will keep getting charged $50 22 more times which is completely unacceptable! This phone frequently goes for $800-1000 online!

For two months I have spent many frustrating hours talking to different CS reps across different departments (Fraud dept, Billing, Mobile Billing) and not a single person has been able to help me after countless ECM tickets (latest one: ECM0015020292). One agent even said the that the first agent I talked to (who helped me setup the router and buy the phone) was a fraud and they would be terminated! So are they admitting fraud within their own company? What is going on? The lack of professionalism and accountability has been astounding! There is no number for a US helpline and I keep getting international call center CS people who can't or have no ability to solve this. Everyone keeps talking about this mythic "back office" who have not given a single update to any of my ECM tickets. I see many people face this same issue online and post on reddit and here so this is honestly my last attempt. This is my last resort to help fix this issue and if I dont get a solution, I will need to return the phone and lose everything I have setup. I will cut off my home internet connection as well and never do business with the company again if there is no solution. I really hope someone can solve this because this has been one of the most taxing and hopeless experiences of my life. So I would really appreciate if someone can help me with this.