Expedia Inc: 333 108th Ave NE Ste 300 Bellevue, WA (71000802)

Expedia.com web app sold me two tickets, departing an hour apart on the same day. Instead of packing and preparing to enjoy my trip, I've been on the phone with their customer service for at least an hour.
I didn't buy two tickets. I remember shopping around, but I specifically don't fly delta airlines but I was charged for a ticket by expedia.com. A month after browsing on their website, I saw an affordable ticket that I wanted to purchase. I only discovered that I was charged for two ticket purchases for the same days and times when I received confirmation notices for both 24 hours before my flight.
I received no apology from these scammers. Their foreign customer service representatives passed me from supervisor to manager for over an hour before reluctantly canceling the cheaper flight.
Why would they ( expedia.com) sell the same person two flights departing an hour apart and arriving at the same time? I definitely, specifically did not purchase the first delta flight I shopped for. At the moment, I am waiting for a manager ( instead of packing) as I have for the last > hour.