You could get them with that seems how the pulleys req adjusting for correct fitment
If you can get an automata print out of how to do the cambelt then if they deny that you don't adjust the pulley for correct fitment you can claim they fitted the belt incorrectly which resulted in the belt failing
If you can get an automata print out of how to do the cambelt then if they deny that you don't adjust the pulley for correct fitment you can claim they fitted the belt incorrectly which resulted in the belt failing