I am trying to figure out how he managed that..... You checked it by setting the cranshaft pulley at TDC. And the marks on the camshaft sprockets are off by that much?

I don't know if there is enough slack with the tensioner removed to correct his mistake without taking it farther apart?

Loosen the tensioner and undo the four bolts holding the sprockets to the cams. (Careful, don't drop them in the motor like one of the other posters did) Undo the top chain guide and see if you can get the chain off one of the sprockets.

OR

take it back to the mechanic and make him fix it right.

Tinker