Why isn't AC air coming through all vents? on 2000 Ford Taurus

I just got my AC line replaced, and they charged the AC. I now have AC, but now the air only comes from the floor and de-frost! There is no air, or HEAT coming from the middle vents(the ones pointing to face or chest) at all. What could be wrong? Do I need to return the car to the shop who fixed the air?

Asked by for the 2000 Ford Taurus
take it straight is there fault...
1 more answer , 1 more comment
If this just started AFTER the work, possible vacuum supply line unhooked from under hood. Let the shop check it out.
Yes all the vents worked before they replaced the AC line.Okay I will have them look, Thanks