Precision 7910 Work station

This was a replacement that Dell sent to me on Jan 4, 2016. On Dec. 12, 2016 my Precision 7910 would no longer boot. After a week of trouble shooting Dell had a technician bring a new motherboard out and install it. but it did the same thing. He called Dell and was told to do some trouble shooting.

I call my technician and after having it approved by his manager he sent me another 7910. After I hooked it up it did the exact same thing. It would not boot. It would only boot to just past the Dell logo. Also it would not run the Dell digestions. I again called dell and talked to another technician and then to his manager and as all ways I had to do some trouble shooting. Doing the same kind of stuff that I and another technician had all ready done.

Then they said they were going to send me another computer. After waiting a week I tried to email my technician but I could not get any replies I called dell and spoke to a manager and he set me up with a technician. After an other week I still didn't get any thing so I called dell again and  the technician said he was going to ship it that day. A week later I got a Rack Mount computer. Needless to say I could not us it. So I called again talked to a manager. The manager and I agreed that the best thing to do would be to sent me a new computer and replace the 8 drive cage and also replace the SSD boot drive. The manager said he would have this system shipped right out to me. After waiting another week the technician said I had to send him proof that I bought the 8 drive cage from dell. So after I found my receipt and sent a copy to him. Finally on Feb. 10, 2017 my technician said he thought my new computer would ship on Feb. 12, 2017.

Then on Monday morning I got a call from my technician's manager telling me they were not going to send me another computer until they had received the other computer back they had sent  me. So I checked the tracking number. And Dell received the old system on Feb. 3, 2017 and dell still has not sent me a computer.

I have not had a working computer since Dec. 12, 2016. I have used Dell computer for Twenty years and this is the first time I have run  into something like this.

What can I do?