purchase and customer service

so I made a recent purchase on alienware aurora r7 for about $2,000 but I mistaken the credit card policy and my purchases was on hold so I contact the customer support and I was ask to contact the card company for authorization and I done so. when I called back to the customer service, I asked if I could split the amount, the agent said it fine, and as she process I receive message on my phone that the purchased was been made but in the end she told me that my purchase was still on hold. from there on I had to call the card company and dell back and forward and can't get my problem fix. And later when they have tried to process my purchase 5 times as it keep on declining, I found out that I was charge twice on my card. Not only that, the purchase is still on hold. when I try to reach the customer support what they do is transfer me around through different department and keep on asking me to call the card company,which I have done several times, the worst part is the agent ultimate hang up on me when I'm not done with my sentence! I always heard dell have great customer service, but too late i realized it is myth. can anyone tell a way to get my money back?