When I contacted Xbox support about my faulty Xbox One on November 24th, I was given service number and the assurance that my replacement Xbox One would be arriving within two days (and this was backed up via an email message). A hold was also put on my credit card for the replacement amount. Today it is a week overdue so I called Xbox support and was told that due to a "processing error" many of the replacements confirmed during the first three days after launch were "lost" somehow. I was told that my new Xbox One should arrive by next Monday.
My problem isn't so much that my replacement unit was delayed, my problem is the lack of transparency and honesty by Microsoft. Once the processing error was discovered I should have been notified immediately, particularly since a hold was placed on my credit card. I was worried that maybe the replacement was stolen from my porch while I was at work and I would be held liable.
I shouldn't have had to put in a call to Microsoft because the onus was on them to contact me.