AT&T unilateralerally changed the terms of my agreement and sent me a $25 bill for a service I never used, but had access to. I have refused to pay and have canceled the service - yet they keep sending me a bill. I'm happy to throw away their paper on a regular basis, but now they're threatening to report me to the credit agencies. While the bill is not high, what they did was essentially fraud in my eyes and I'd like to avoid paying this bill at all costs. How serious is the credit report threat and the repercusions? What are my options?