Wheel alignment

I taken my VW Polo for wheel alignment and the front fender was damaged on more or less the same spot on both sides, taken it back to them and owner says it can never happen while they doing alignment, he says the camera does not work, he failed to accept that his worker could have made a mistake. Will not recommend anyone to take their vehicles there. He put my vehicle on the ramp and showed it does not touch, he should have put the alignment back to its original reading and then he would have seen that his worker was negligent.