If there's no assist in either direction, it's the pump. I'm guessing the mechanic didn't have access to a power steering analyzer to check flow and pressure from the pump, and honestly, that's the only way to be sure it's operating correctly. That being said, it's hard to place blame on him since it was checked 7 months ago. Pumps aren't difficult to replace and any shop manual should have the procedure in it. remember to flush the system or you run a risk of damaging the new pump.