Make sure the bead of the tire is seated properly on the wheel. Have some one mount the wheel and tire on a balancing machine and spin it. Observe if the tire appears to hop up or down while it spins. If there is a hop break down the bead and turn the tire on the wheel, say maybe 90 degrees, keep doing this untill there is no longer a hop. If that doesn't do the trick you may have an out of round wheel or tire. A shop with a run out guage should be able to determine if there is a problem. You may also want to find a shop with a road force balancing machine. If the wheel is non hubcentric it is also a good idea to gradually torque down the lugs with the wheel and tire off the ground.
Or more than likely the shop just doen't know how to balance a tire.

Even though it's a reputable shop, Igor the technician, (high school kid) may have been doing the work. A reputable shop doesn't mean everyone there knows what they are doing. I've taken cars to reputable shops that didn't know their *** from a hole in the ground.