Cracked windscreen from stone chipping from men’s trimming / clearing vegetation on the side of the a38

I was driving southbound on the a38 at approx midday on Friday 14th March when my windscreen was hit by a chipping that was due to men strimming the path on the side of the a38. There was no signage, no near side lane closure to enable for this to occur safely. At the time I thought it just hit my car, but on arrival in plymouth I noted that it had caused a crack which requires replacement. This is being done on Wednesday but the excess of £135 will need to be paid by me. I am frustrated that the carelessness of the workers has caused me both time and expense. Please may this be looked into to compensate me for the damage but also to ensure similar events do not happen in the future and such activity is not enabled without proper safety procedures by the side of a fast road. This could have caused a serious accident.