What recourse do I have in regards to suing this company?

[Lil Mama in VA]

Hi. For the past three months, I was an independent associate for MCA(Motor Club of America). Well, I have tried to make sales so that I can be successful, but that has not happened at all. I have promoted products for MCA through facebook, twitter, youtube, etc as well as offline marketing. I received a letter today from a law firm, stating that if I have until October 26 to write the firm, saying that I will stop marketing MCA. If I don't, the letter states that it means that further action will be taken against me. Well, as soon as I read this letter, I contacted MCA and was told that there is nothing wrong, and I have the right to sell. But , I am beyond ticked off and decided not to promote them anymore. I have also contacted the law firm to see what is going on, but of course they are not there because it's during the weekend. What can I do? Do I have the right to sue?
Maybe you are not understanding. How is it a mistake? That's what I don't understand. In plain English, how can a company allow you to be an independent associate to promote their products but contact a law firm, stating that I should cease? Please no sarcastic answers. I have the right to be upset and if you don't like it, you can shove it.
To Sea, yes I have proof that I am an independent contractor. I don't know how I came to this. There were some frauds exposed with the company. Not me but some others. I just want to know what steps to take.