Unlimited Plan Pricing History

Hello

Im hoping this can be escalated to the right supervisor or expert. 
we signed up for Xfinity Mobile Unlimited sometime late 2022 and I have billing statements since January 2023 for $80 for 2 lines.

I just found out that Xfinity Mobile Unlimited is $60 for 2 lines. Why were we never notified of this option and why were we paying $80 for the same service over the last 3 years?

Im disappointed in the nearly $800 overpayment for the Unlimited plans. Can we have a special credit issued to us or upon trading in our existing iPhone 11s can we have the difference in cost waived for iPhone 17s? My understanding is that our existing phones are only worth about $400 in credit but if we can get new iPhone 17s for no cost to us we would be satisfied. 

Thank you,

James