Help with Exchanging Refurbished Computer

I purchased a dell AIO refurbished computer for my 70 year old mother on December 9, 2015 for a Christmas present.  We received the computer in a timely fashion.  However, when I opened it on December 26th the computer did not work.  It would not turn on.  I called technical support and they told me the "refurbished" computer was never fixed.   It had the same issues with the previous owner.  So I began attempting to contact "customer care/support".  I spent over 10 hrs on the phone with numerous customer service reps who just either passed me to someone else or kept me on hold for over an hour.  Finally, I was able to contact a return specialist who agreed on December 30th to perform an exchange.  Once again, after several hours on the phone, I was told it would take 10 business days.  It's January 26, 2016 and I still haven't received an exchange.  Does anyone know how I can escalate this problem???  Is there a number to call other than the customer service number?  No one I spoke to really cared or seemed willing to help.

Thanks