Surely they centered the steering wheel during the alignment ?
Try finding a flat,empty parking lot .With no hands on the wheel & at slow speed, does the car 'pull' to either direction?
Consider rotating the tires if possible - check sizes F/R, L/R first. This is in case there is a tire problem that only shows up when driven. The other thing to consider is finding a place with a Hunter "road force" alignment machine. Other Forum members will comment on how relevant these suggestions are.
Art's Automotive, We Don't Just Install Tires -- Correcting For Road Force Variation and Lateral Force Pull.