My wife and I won a two night stay voucher from JW...

My wife and I won a two night stay voucher from JW Marriot at a BMW of San Antonio event. We went ahead and used the voucher on 7/5/19 - 7/7/19. Now, a week later, there is a charge on our credit card for the full amount of $1,400.00+ . We tried contacting the resort and they transferred us over to some third party site to file a dispute. I told them that if I knew that this was going to happen, I would have not used the voucher at all. They seemed to be giving me the insinuating that we didn't have a voucher at all. They asked us if we have the voucher with us, which we don't because they asked for it and kept it during check-in. We are now awaiting the 'dispute' to be processed as they conduct their investigation to see whether or not we will get put money back. For such a well respected hotel, I cannot believe they are treating customers this way.