Unresolved Warranty Issue

Due to a warranty issue with my computer, tech support ordered a replacement video card on Wednesday, Nov 8th. 

Was told I would recieve an email with dispatch number..... didn't happen

Called evening of Friday, Nov 9th to inquire.   Was assured part was in stock and would receive on Saturday Nov. 10th...... didn't happen

Called afternoon of Monday, Nov 12th.  Was assured would receive part on Wednesday Nov 14..... didn't happen

Called Wednesday Nov 14.  Was told that because supervisor had opted to upgrade the video card the process takes longer.  He was unable to give any additional information.  Is this an acceptable response under the circumstances?

Called Thursday Nov 15th.  Was told I would receive a phone call in approximately 2 hours with updated status of part in question...... didn't happen.

Computer has been down since Monday, November 5th which results in my inability to work for two full business weeks so far.

I could have replaced the video card myself by ordering a new one online or even getting one locally but don't feel I should throw good money after bad when the warranty on this computer is still valid. 

If I would have gone this route would Dell reimburse me for the cost? 

Why is it so difficult to get any valid answers to this dilemma?

**Update while creating this post call received from Dell technician.  Part to be received in 2 to 3 business days.... Hopefully???