is running a risk here, and it's exactly as you say, you - and thousands like you - might easily vote with your mice, unless they buck up their ideas. This isn't the way to conduct a business. It creates tremendous resentment, and they of all people should realise that. I'll not mention their name, as you haven't done so, but I think they'll pay a heavy price if they don't reduce your subscription rate, and if I was in your shoes I would be making a polite, but very firm point to them.
Some months ago my ISP reduced the cost of their broadband service to new subscribers. At the same time they reduced the rate to existing subscribers like me, and created an instant feeling of loyalty & goodwill. It isn't rocket science, and I'm very surprised that your company hasn't got the message that customer loyalty is the stuff of which ISP dreams are made.