National Business Publishing Corporation They copied my signature from 3 years ago and are trying to make me pay for listing I did not order. Houston, Texas

Three years ago I got a fax for a free company listing on the internet, I signed it and faxed it back, then I got a bill with the fine print I didn't see blown up showing I had to pay a couple hundred dollars for the free listing. I paid and thought that was the end of it.
Now they are faxing me another bill every couple days with a copy of my signature from three years ago demanding payment again for $199.00 I only signed once three years ago, and wont keep paying for my one time mistake.
They are rip offs, and I want to make them leave me alone.