Dunn and Bradstreet uses false statements to get people to pay for their services, Internet

I have a small business that is registered with Dunn and Bradstreet. For the first few years there were no issues but within the last couple of years, things have changed. In 2008 they contacted me to say that my credit rating had changed and I should take a look at my rating. Unfortunately the only way to do this is to pay for a service that allows you to see details about your account. I really didn't want to but I decided to pay the ~$400 so I could take a look. When I looked at the report I didn't see any problem. I had intended to get back to them and discus this but I got busy and within a few days the issue had passed out of my general awareness i.e. I forgot about it.

About a year later I got another call and was informed of the same thing. I don't remember the call in detail but apparently they wound up signing me up for another year of the service that allows you to see your own rating in detail. In a few weeks I got a bill for $449. I immediately wrote "Please cancel" on it and sent it in. I thought the matter was closed but the next month I got another bill. Again I marked the bill and sent it in. After getting another bill I called them and they told me that I didn't follow the correct procedure for cancellation and that it was too late to cancel.

I have never used this service and requested cancellation several times. Now it's in collections. I have a real problem with paying for something that I did not request or use.

I consider D & B to be using extortion tactics to get people to pay for their services and think that something should be done about it. Does anyone know how to go about filing a class action suit?