Claim for windscreen not processed.

I have been struggling to get through to the claims department and finally got the opportunity to go to a local service provider for assistance. They got through via Auto & General after the 3rd try. I need a way forward on a claim for a windscreen for one of my vehicles as the original damage happened a couple of months ago due to road works on the N12 (way to work). I cannot specify an exact date or time that the first incident took place as I repaired a couple of chips due to lose pieces of tar/stones on the open lane of the highway. The N12 between Emalahleni and Ogies has been completely re-done the last couple of months. Due to this reason, I did not want to replace the windscreen after the first crack developed. Reason for claim not submitted is that I cannot stipulate a exact date and time for the first instance. Am I forced to fabricate a date and time in order to replace my windscreen via the insurance? Kindly contact me with a way forward.