Website errors, coupons not applied, customer care total fail!

TLDR: Dell customer service can't fix invoice errors, doesn't understand invoices, doesn't understand product prices, can't understand coupon codes, can't cancel orders within 1 hour, can only offer more coupons to try and satisfy customer. Orders only "cancelled" 15 days later once it ships (whatever that means)!

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I've just experienced customer service that's so bad one can't help but wonder how Dell stays in business. I purchased PC a couple days ago, using a 10% off coupon for joining the mailing list. Coupon was accepted, and purchase completed, but at the final step the following error on the site: 
"We're experiencing downtime. We'll attempt to re-submit your order."
The message continues telling me check my email for the status, in a couple hours, and that I may need to resubmit the order. 10 hours later I receive the email confirmation that the order has been processed, and then another email with the invoice. But the price is wrong, my 10% off coupon was not applied. I call customer care. Customer care checks records and says, "I see your coupon was applied at 12:30". Yes, that makes sense, that's when I made the order. Then, why is the invoice price wrong I ask? Customer care tells me it's because I purchased other items with the computer. A 12 month subscription to McAfee. Impossible, I reply, I did not, and besides, the price I was invoiced is the price of the PC without any extras! After some confusion and me checking my invoice, I go to the product page, and notice that a 12 month subscription to McAfee is included for free. So that's not it. Now I am told, the coupon was applied, it just doesn't show up on the invoice! Confused I ask, but why does my invoice and order confirmation say "payment type Visa: total $xxxx", which is the price of the computer without a discount. Because that is the price with the coupon applied, I am told! No, I reply, if you go to the product page on the site, you can see that is the price of the computer with no coupon applied. But customer care just continues, that the coupon was applied, and I am confused about the price! I tell her the price was $xyz when I submitted the order, reflecting a 10% discount. Furthermore, the product page shows the price, clearly no 10% off discount has been applied as evidenced by my total price (which she can see on her end). This is already about 20 minutes of discussion. Exacerbated, I tell her, "You know what, don't worry, just cancel the order. My wife has the same coupon, I will get her to resubmit the purchase on the website, that will clear up the error.". At this point I'm told the order is already in production, and will only be cancelled when it's shipped 15 days hence! What on earth does that mean?! I explain, that's no good, I need my credit card to be cleared up to redo the purchase. Customer service then asks me to just keep the order as is, and she will send me a $50 coupon, and then my wife doesn't have to use her %10 off coupon! No thanks, I just want the discount applied to this purchase, or simply cancel the order and I will redo it online! Nope, can't be done. And the hold will be on my credit card until the order leaves production. So 1 hour after I received the order confirmation, the order goes into production, is stuck there for 15 days, and can't be cancelled in the meantime? And you can't understand that my 10% off coupon was not applied? And BTW the above interaction took 30 minutes, after every bit of info I supply, the response "ok just stay on the line while I look that up". Like dealing with a used car salesmen where they try and take time to get you invested on just accepting their offer. Amazing!

December 3 = The refund is closed on credit order. The refund will post to your original mode of payment in 1-2 business days.
DELL-Cares