This was some years ago but I decided it wasn't worth the cost for me so I went inside my settings to cancel. Their stipulations for cancelling the membership were "Come back 2 days before the account is set to auto-renew and cancel then." Excuse me? That was in like 6 months. Can't remove the credit card. Can't ask them to just stop auto charging.
I set about 40 calendar reminders and cancelled at 12:01am 2 days before auto renew and then nuked my Amazon account.
Dark patterns. Dark heart.