Extremely unhappy about warranty service!

I have a Dell XPS 410 that started acting up more than a week ago.  The problem was first diagnosed as a bad video card; I was sent one within three days and installed ib, but that turned out not to be the problem.  After more diagnostics, it was determined I needed a new motherboard.  That was last Thursday, a week ago.  Since then, I have received daily calls from a recorded message at something called QUALXSERV, which purports to represent Dell in thiis area (upstate NY) each one saying that they are swamped with business and can't repair my computer today.  I was finally able to reach an actual person at Qualxserv, who identified himself as Peter.  He said his company did service work for Dell (and others) in my area, and that they were swamped with work and couldn't possibly get to my computer until sometime next week.  He made it quite clear that he couldn't care less when my computer got fixed, and that it was by no means certain that the repair could be accomplished next week.

My understanding of the warranty is that Dell undertakes to have warranty work done in a matter of days, with night service involved if necessary.  Peter said there was no night service, and no service tomorrow (Friday) because it is a holiday.

It seems to me Dell should be more responsible than this about its warranty work.