Difficulty Cancelling

I put in a request for a cancellation to my subscription to them but I can't seem to get them to understand that I want to cancel. They just keep on lowering the fee and then send me a sample of a new product of theirs but they won't allow me to cancel. I'm starting to wonder if I even have a right to cancel my subscription to them. All I want to do is cancel my subscription, that's all too it. Just cancel it.