when they have it opened again, look at it yourself and see if there's scrape marks on the drum friction surface, or the ends of the short shoes, also if any hold down spring washers look brand new compared to the rest, they may have "touched up" something without mention it and the symptoms you describe could be caused by shoes slipping out of position, particularly because of a hold down popping loose, which can happen .... and after it's fixed up DO find another shop, a brakeman who says the shoe position doesn't make any difference is either plain incompetant or lying
Bill
