LOL tell the shop they need to get their eyes checked
there are camber tabs in the rear... the only problem that arises out of them is that the tabs start getting old and bending... so they prefer not to change them in case the tabs break which then you would need to get them welded up again...
ask them if they will adjust it for you and show them the tabs on the rear arms... it could be that it's not that they can't do it but they won't...
let me know how you get on