Internet bill is suddenly become high

All of a sudden, I started seeing $42 increase in my bill due to some promotion ended for which I was never informed on beforehand by email, mail or any kind of notification from them plus additional $4 increase in the billing because Xfinity has upgraded their systems and they want to lute(i.e compensate) their operational costs(basically upgrades to their system) for which I am NOT going to extra 1mbps high speed as part of my internet plan.

Some maths here, 3% increase of the original bill($4 in my case) is announced by Xfinity and with approx of 10M subscribers, xfinity is going to get

10M * 12months * 3%(min 4$ I am on a medium speed plan) = $480M which is wow. Xfinity charges their customers for their systems that got upgraded and they got new infrastructure established i.e basically should be covered by Xfinity operational cost.