It is difficult to answer your question without knowing what you signed and the specifics of the service you agreed to. If you still have the paperwork you signed the first step would be to review that material which may contain the answers to some of your questions. Without it, it would be very difficult to advise you on this issue. Though you CAN file a lawsuit if you believe fraud is at play, the issue here is that you may have very limited damages that make it not worth your while or worth an attorney's while to proceed. If after reviewing your material you feel that you wish the discuss the matter further, find an attorney who practices plaintiff's consumer law and he or she may be able to assist you further.
This response is my opinion based on limited information and should not be taken as legal advice. By answering this question I have not formed an attorney-client relationship with you. I am licensed to practice law solely in the state of Georgia and am not familiar with the laws of other states. Please consult an attorney in your state to obtain legal advice.
Cases like this unfortunately only can proceed as class actions, due to the low damages: in your case, between $10-$18 per month. We would need to examine the documents you signed, and the solicitation(s) you received, to understand (1) whether you have a viable case for consumer fraud, and (2) what venue such case could proceed in, ie court or arbitration. Feel free to give us a call, and we will try to assist you