Dont care about after service

Last Friday i fitted a windscreen on my vehicle . On a trip i passed a truck carrying small stones they use to tar roads. These small stones chipped and cracked my windscreen. Windscreen is called Benson...i called Glasfit only to be told i need to pay R375 per chip and i have 2 chipsto repair them , this is even more than the excess i paid on the claim . This is after fitting it last Friday and incident happened on Monday. Can such small stone as that used to tar roads chip the windscreen or is the windscreen the issue. I had a genuine VW glass on my vehicle and it took a while before actual chips happened. Youd expect that after a few days of fitment the customer would get some support , but instead im just told to pay R375 times two after fitment last week , which now seems like an inferiour quality windscreen