Can a travel club charge me a fee to cancel when it is not in my contract with them?

We are members of a travel club and they have been billing me over and over again telling me I need a release to cancel. they keep mentioning my contract with them. I reviewed my contract and there is no c clause that says I can't cancel or if I can there will be a fee charged. I told them this and they responded, Yes I do understand sir. There is no clause for a release. We have had documents drawn to do so. Can they change my contract without me approving iy. I was never notified about this and never given an opportunaty to accept of decline this change. I live in Florida and the address for the company is in Illinois.