unsubscribed but charged for 2 years running anyway...

In March 2014 I cancelled my subscription to Norton after an auto renewal email arrived. Over a year later, checked my credit card statement for this July and find I've been charged a renewal fee! I checked this out with Norton online support and they fixed it pronto. So far so good. Then I check my statement for last year (July 2014) and find they charged me last July as well! This time around not so helpful. Norton will keep my money because I failed to pick up the error on my credit card statement last year and a 60 day period has passed. I wonder how many other people have been charged in error in this way and that Norton is hanging onto their money too?