International Credit Fraud

[LetMeSpin]

What is the name of your state (only U.S. law)? Texas

All of the following takes place in the Sultanate of Oman, where I work as a school teacher:

This past April, I made the mistake of allowing a friend of my girlfriend to use my credit card as a security deposit on a car leasing. Our agreement was simple, he didn't have a credit card but badly needed to rent the car on his holiday, and he would pay for the car in cash at the end. I can't be entirely sure of what happened, but my credit card was charged for the full amount of the rental (nearly 2000 USD). I went to see the company, and they showed me a sales slip where someone had signed for the purchase, using my card somehow, "C.Wacked." My first initial is C, my last name is certainly not Wacked. They, the company, are adamant that no cash was paid. My credit card company's dispute department has advised me that I have basically no grounds for a dispute because I did agree to a pre-authorization at the beginning.

It has been difficult to contact this friend of my girlfriend, but he claims that he paid cash for the rental, although he has no receipt. To further complicate matters, he is a UK resident, and I am American. I'm really not sure what course of action to pursue. Are there any options available to me?What is the name of your state (only U.S. law)?