xfinity mobile part of bundle promotion LIES

I was offered a bundle promotion deal on April 30th, 2025 that would increase my internet speed for a lower price if I got an unlimited free mobile line. I was reassured that my bill in totality will not exceed $70/month. I am now being charged for the device. I recently canceled my mobile service and was instructed to return the device to a nearest store. When I tried to return the mobile device in store, the store supervisor told me that my account notes didn't reflect the instruction to return the device and that I have to pay off the device. 

None of this was disclosed to me when offering the promotional deal. I am stuck with this payment I never asked for. I have contacted support several times and have receipts to show what was discussed. I filed a dispute via the website outlining the charges per billing statement and interactions. This is ridiculous and dishonest. I will never accept a promotional deal again!