the 2 idlers both have a spacer, the upper 1 is short, the lower one is longer, he could mix them up, but i highly doubt he'd be that stupid
your tensioner was 180 degrees off and the belt was flapping around that much it had rubbed the case, so i retract my comment LOL!
Just trying to help buddy. If I were you I would go collect your car and take it to a competant garage. For a list of the competent garages have a look in the traders section. The only trader I have experience with is BTM (Fred). They did my cambelt, aux belt, dephaser, and a 12k service. They come highly recommended and that's not just from me.