Forgot to cancel Amazon Prime...now what?
If you haven't used your Amazon Prime membership since your credit card was charged, then you're eligible for a full refund, even though your trial period has already ended. Otherwise, you have three days from when Amazon Prime charges your credit card to decide whether you still want to cancel.
Amazon customers are only eligible for one free trial of Prime every 12 months. That means, if you cancel your membership and decide to give Amazon Prime another try you'll have to immediately start with the paid membership. If it's over 12 months, then you'll have the option to try the service again through a 30-day trial before you'll need to pay for a membership. This is handy if you want to shop Amazon Prime Day deals without paying for a membership.