I have a landline I barely use. 50 calls a month, and I only make 3 or 5 at most each month. I found I barely make long distance calls, and with the per call charge and all the fees, the cost is ridiculous, $5.72 for only a 1 minute call one month, the only one I made. I want to stop long distance with ATT because the cost is too high. I was told I would have to pay a fee to stop the service. Can they do that? Make me pay to stop?

If you signed a contract, then yes.

Yes, using THEIR service they can pretty much charge you for anything. It's in the fine print somewhere, trust me.