Subscription auto-renewal is mandatory with requirement you cancel several days before auto-renewal. I cancelled by email sent 2 days prior to the auto-renewal deadline. Five days later, they acknowledged my cancellation BUT applied it to the following year and charged my credit card for the 'current year'.
I disputed the charge at Citi Visa, but Casey Research reported I had acknowledged their terms and had signed up for auto-renewal. They IGNORED the date my request to cancel was sent and used the date they actually read my email.
Having only some of the emails, with no postmarks or other 'proof' I was unable to adequately support my dispute at Citi Visa.