Why charge people for supplying their own modem

I returned my Xfinity modem and was told that it would now cost me MORe to have unlimited data. The modem I am now using is faster and gives me better coverage around my home. Why does Xfinity feel charging more for less is a good business model?

My solution was to cancel my cable subscription. I rarely used it so it was a no brainer to save myself money. I’ve been a customer for over 10 years and feel like it means nothing to Xfinity. Now Xfinity lost a cable subscriberf just for being a little bit too greedy.

 I understand that the reason is bundling, but to me it’s more like bungling.