Hello!  The first person you need to contact is your bank.  They can place a hold on the funds and initiate fraud proceedings in regards to the charge.  They are also the ones who will most likely halt your card and issue you a new one with different numbers.  
I have a "Pending" charge on my bank card for $529.99 made yesterday. I have been transferred 6 times and am still holding and have wasted 30 minutes of my day. I am trying to get this resolved asap so that those who stole my card number do not get the merchandise and also so that I can have that charged reversed. I've been asking for the Fraud department and am told there isn't one. I've been asked for an order number 6 times which I obviously don't have. This is so frustrating.
Fraudulent activity on my bank card - transferred 6 times and still holding