Chip repair turned to a crack

I took my car in today (04/10/17) for 2 chips repair at PG Glass Centurion. I called the insurance (Momentum) and two claims (Claim ********** & ********** ) were approved. When the workshop finished with the repairs, they told me that the second chip did not work out well and they will only process 1 claim. When I inspected the car, I found the chip they were supposedly repairing has turned into a 20mm crack, much worse that what it was which was about 3mm. They told me to drive with it as is and if it propagates I must bring back the car for a claim to be changed to windscreen replacement. Who is responsible for the damages? This is not acceptable