If the paint shop didn't get a chance to "buff" it out then it sounds to me like a clay bar might not work for you.
A clay bar will lift off such things as industrial fallout, paint overspray, disc brake dust, tree sap, acid rain, oxidation and other nasty contaminants that have adhered to your paint's surface.
But if the paint itself is rough, you really need to have it buffed or even color sanded then buffed. Both of which, if your not familiar with, I'd recommend having done by a professional.