Try rotating your tires, also, check your air pressure.

 

They should have checked the tire pressure before they did the alignment. If your drifting left, increase the pressure on the left tire by about 5 psi higher (or lower the right 5 psi) hen the right. It may help level it off. But I don't know how off it is.

 

4 new tires and alignment. Same problems...

Does it drift to the left, or is your steering wheel just not cantered going down the road? It can be within specs and still not centered. It took me 4 trips down the road to get mine centered after an alignment.