Im really sorry you had such an awful thing happen on your trip.
Once they have your credit card info they can charge anything on it,
My mom had called and asked to extend our stay one morning and told the cm she would come down to pay, she didnt want to use her credit card.
Well when my mom went down to pay they informed her that they already charged her card on file. We didnt have charging on our room keys either.
My mom was mad and the manager pointed out that when you sign the paper when you check in(not express checkout just the normal paper you have to sign) , you allow them to charge anything to the card you used to check in with.
I hope you get your money back,