Priceline.com Priceline fraudulently billed my credit card after NOT accepting my price offer. Internet

I tried using priceline.com, made an offer on a hotel room for Buffalo, they rejected my offer, but billed my credit card anyway for $250.00.  I did not check into the hotel...all I did was make an offer on priceline.com, the site gave me back a message saying they could not accept the offer, so I exited the site and assumed because they did not accept my ofer that my credit card would not be billed.  I got an email from them the next day telling me to try again using a higher price, or different criteria, but I did not.  The credit card company has been notified.  When I contacted Priceline they refused to do anything about it.  How can these people get away with such blatant and fraudulent activity on people's credit cards.  I will never again use any online service that asks for my credit card upfront before agreeing on a price...that should have been a clue to me.  The fact is, the sit is fraudulent, and a scam, and no one seems to be doing anything about it.