SiteStar Cancelled by AMX, but turned over to Windsor Collection Agency Lynchburg, Virginia

I used the InReach ISP only because I had an existing web page that I updated for a charity that I started when the ISP was WombatGuild (excellent). I kept the email address, too, but mainly used a national internet account because that provided my DSL line.

I was never able to update my Web page after SiteStar took over, and was never able to contact anyone in technical support. Once I did see a Web page that indicated Web pages were going to be made available, but I was never able to access the server to update mine. After almost a year, I stopped the service and contacted American Express to investigate if it was legitimate. After several months, the American Express investigation could not determine that the "Catalog Company" charge on my credit card was legitimate (no response from any human being, I believe), and cancelled the two months of charges and refused to add more.

Some months later, I received word that my account was going to be closed per my request. Several months after that, I started receiving calls from a Windsor, Canada collection agency saying that I owed SiteStar money. I explained that American Express had stopped the payments from SiteStar, not me. A "Miss Allen" was screaming at me as I tried to explain. I said that I didn't think it was a legitimate company. Afterwards, I did a quick check on google and see that SiteStar has an "F" Better Business rating, and has half-a-dozen complaints on this Ripoff Report site after customers have stopped service. 

I suspected that SiteStar was less than ethical and would continue to charge (and maybe no one even worked there--I imagined it was run out of a phone booth), which is why I contacted American Express. 

How do I stop Windsor Collection Agency from wasting their time? I'm going to file complaints with the Better Business Bureau and California consumer authorities.