Charged for free gift card

Hey hi guys. I recently bought an ipad through apple online store with educational discount. I was charged twice for the gift card. I got two invoice 1. (Ipad + giftcard - giftcard) 2. Giftcard. Is this normal?. I tried contacting apple customer support they said that they'll put a ticket for me and I got an email from apple regarding the ticket. Email: "We have been unable to process your request to reverse the pending authorization on your account. Please contact your card issuing bank for further assistance". Why should I contact the bank for apple randomly charging me?.