Charged for a trip I never received confirmation for!

On July 13, I booked a trip for Chicago, August 9th weekend. I did not receive a confirmation email so I called back on July 16 to get the information and was told by Expedia that there was NO record of a trip being booked. I even gave them my credit card number and again, they told me that no trip had been booked. I did not re-book or take the trip to Chicago. On August 13, I opened by credit card statement and found that the trip had been charged to my account. I contacted Expedia and they found that a confirmation had been sent to and account at "@sol.com". My email account is "@aol.com".
Without a confirmation, I did not know the trip had been booked. When I asked for confirmation I was told the trip had not been booked. Now, Expedia refuses to reverse the charge or credit me for another trip. According to Expedia.com, which is "extremely sorry", I am out $676.25 for a trip I never knew had went through and therefore never took.