Refusing delivery is indeed your best option.  Dell will tell you that it is not their preferred way for you to handle this situation and that it will delay the refunding of your purchase, but since you were smart enough to use a credit card my experience is that their claim is simply not true.  And accepting delivery opens the door for them to charge you a restocking fee as the unit become considered a return rather than not-delivered. I also recently had a colossal fail with a $16,000 Dell PowerEdge Server order.Successfully entered the order online, got both the order acknowledge email, and then the order acceptance (aka they were able to charge the credit card), and was given a expected delivery date.  Then the fun began...  order delayed once, twice, then three times.  Each time calling customer service and being told to wait, but no items are on backorder, a problem with "logistics" (whatever that means, the person that said it certainly did not know what it means).  On to posting in the forum and a seemingly friendly moderator offered to look into it but never did.  On to writing Mr. Dell (not sure I can post his email here so email me privately is you want it) which yielded a call from a 'escalation team' person that despite an absurd amount of calls and email could never tell me the reason for the delay other than that it was a 'configuration issue'.  Without explaining the reason he somehow wanted me to reorder, for what, so I can waste more time to have that order fail too? No concern was expressed about why their system accepted an order that they could not build.  I think this was not something they ever considered as they clearly have no procedures in place on how to communicate a fail like this to a customer.  Not a call or email from manufacturing, not a customer service person (or supervisor) that could figure it out, not a Community Forum Moderator, not a member of Mr. Dell's escalation team.  A total fail.   And this is not a desktop or laptop but a Server, the most profitable division of Dell as far as I know.  Guess who I will be ordering from instead?  Not Dell!
Went to place an order for a very expensive laptop.  Order did not go through (page basically said unable to process order).  So I tried again and it went through.  Awesome.   Found out an hour later that I now have TWO orders. Emailed support immediately requesting cancellation.  No response.  Waited the 24 hours, and called order support and am told (repeatedly) that they cannot cancel my order.  Now, up until this point I would have gladly bought ONE laptop.. but not two.  No can do.  I am told they can't cancel it.  I ask who CAN cancel it.  I am told that nobody can cancel it.  Basically, tough luck. Luckily I use Amex, and they were more than happy to help with refuting BOTH charges, and I will now be refusing shipment on BOTH laptops, and ordering a new Lenovo instead. I was a long time Dell customer, both personally and when ordering servers, PCs, etc. as a CTO.  Needless to say, this experience was so bad that I will never order from Dell again, either for my family or for work.
Horrible order support.