Why didn’t Norton refund my auto-renewal charges for last 3 years?

Hey all,

Can you help me to sort out the billing issue with Symantec. Let me explain the issue first, I had an account with Norton and registered an official email address while taking a subscription, for some reason I left the job and forgot about the subscription. Somehow I checked my bank account statement last month and found that Norton LifeLock was charging my account for the last 4 years and it was unused, when I requested Norton refund and complained to Norton customer service they refunded but for just one year and denied for remaining 3 years. Can you suggest me what to do or can I get the remaining money?