How do I cancel the charge made to apple.com/bill and get a refund?

My Discover card was charged $99.99 on 05/03 and 05/20. One was to apple.com/bill 111-111-1111CA and the other to apple.com/bill866-712-7753CA. The category is merchandise. These are not authorized purchases. I would like a refund for these two charges.

Please tell me how I can get a refund for the $99.99 I was charged twice at apple.com on 05/03 and 05/20 for merchandise I did not order. This appeared on my Discover Card statement.