How do you get an ETA?

I have a warranty thru MicroCenter. To fix the laptop required more than 4 parts so it was sent to the magic Dell Depot. They said 1 to 2 weeks, I'm coming up on 3 weeks and no one can tell me the status. This is my son's laptop.  He's a grad student and needs it to run his tests and experiments. MicroCenter says they'll try and get in touch with Dell but they rarely answer so he wasn't sure what he could do.  I've been a loyal Dell customer for over 15 years but this may be the end of that! This is ridiculous that a company that big us that unresponsive. How do you get service with these people?