xfinity mobile coming up short

I used to have a Xfinity voip land line I hardly used but I was paying close to $30/month. when I called to cancel that line in May 2025 Xfinity told me instead of canceling they could port the number to mobile, give me free Samsung a26, and bill will be lowered to about $4/monthly . this was all very good. But today I noticed that the last two billing cycles (assume one year after they signed me up in may) they have been charging $40/month. When I called they said promotion was only for 1 year. when I said I don't want to pay, rep said she could downgrade me to $20 plan but then phone has to be paid $12/month. it's crazy that that phone was only free if you keep the plan for 24 months but plan promotion itself was only 12 months. I could swear that all this was not disclosed to me. And this phone even 1 year ago wasn't worth $300. I have emotional attachment with this number but not worth paying $40. ill need to switch if xfinity doesn't go back to $4/month. Can Xfinity look into this?