Discovery Card Disaster

My Discover Card was cancelled over a year ago. In December 2014 an ******* transaction was executed on my account (bearing in mind the account has been closed for a year). Discovery decided to reopen the account and charge me for the ******* transaction plus the yearly card fee. The account was never requested to be reopened and I destroyed the card when the account was cancelled. A dispute form was therefore completed and sent to discovery. Discovery now decided to debit the disputed amount and the card fee from my bank account even though the account was closed and the amount has been disputed. Discovery Card seems to have NO control of their cards as it is through FNB. Even if cancelled the Discovery Card will unfortunately continue giving problems even years later.