Newgg Was told I could use my promotional card on my purchase and then they jack the price up Internet

So I have used Neweg in the past without a problem.  My problem happened when they were offering a promotion for the XBox 360.  You bought the XBox and received a promotional gift card.  I was looking to purchase a computer at the same time so I used their online chat "support" and explained that I wanted to purchase the XBox and use the promotional gift card towards the purchase of a computer.  I was told that wouldn't be a problem, that I should purchase the XBox and then apply the gift card to my purchase of the computer.  I make my purchase, but no redemption code is given for the gift card.  I contact the online support a second time asking about the gift card and am told that they will mail it with the XBox.  I explain that the first person I spoke to said I could immediately use it for my computer purchase.  I was apologized to and told that the card had to be mailed and that they could not give me a redemption code, but the computer could still be purchased when the card arrived at the same price.  I accepted that and waited for my package.

A week later I get the XBox and the gift card from Newegg.  I log on to buy my computer, but now it is $200 more expensive.  I contact the online support and explain that I attempted to buy the computer the previous week, but because of an error on their end I was unable to.  They offered to take $25 off the price.  I explain that this is unacceptable, that I was told the first time I could immediately use the card and then the second time that I could purchase the computer for the original price.  I am now told that the promotion for the computer I wanted is over and all they can do is take $25 off.  So, then I tell them I want to return the XBox and the gift card and am told I can return it, but I will have to pay a $75 fee!  With so many tech companies out there vying for my money why be this way?  I build my own computers.  I maintain my own computers.  You would have made a whole bunch more money from me if you had honored what you said you would instead of going for the quick buck.

The funny thing is that I also do the computer purchasing for my job and so in reality this has cost them approximately $15,000 since the incident.