Odered 8pm last night now they have a 5% discount!

Placed my order for an XPS 17 laptop last night, spent about an hour on the phone with a sales rep. The price he provided me was more than what I could get online. He assured me there would be no new promotions in the foreseeable future and that his price was the bottom line, even though I had it in my cart at a lower price than what he kept saying. I went ahead and ordered it at the cheaper online price, and now today they are offering an additional 5% discount. So I did online chat and they were unable to help since my order has already gone into process, she gave me a phone # to call. Called the number and they pulled up my info, as soon as I told her I was looking to have the extra 5% credited to my order all of a sudden "her tools were down" and I would have to call back in 2 hours. I followed up with an email to CS. Does anyone know if and how I can get this extra 5% applied to my order or refunded to my cc? If the sales rep would have been honest with me, I would have waited 4 more hours before placing the order!!
Any help would be appreciated! Thanks!