File a chargeback to your CC company. Don’t waste your time with Amazon reps after the first call. Chances are they’ll ban you from Amazon which makes it easier to transition to other services.
Separately, I had my bank block Amazon Prime from charging my debit card. It shows up as a different merchant so they were do it and I can still make one-off purchases (which I don't like to any longer). I did this because the UI to cancel Amazon Prime did not work on my new, updated MacBook. It did not respond to clicks on the "confirm cancel" or whatever button.