Insurance Excess

My son accidently walked through the plate glass door of his apartment. Fortunately he only suffered a couple of cuts. However it was a Saturday and when he rang the managing agent they told him to ring a number which just went to a recorded message. It was winter and cold so he got a glass repairer in and was told he had to pay the $1000 bill. We have told him he should not have had to pay. He has contacted the managing agents several times and they have (eventually )said they will reimburse him less the insurance excess. Is this correct? This happened several weeks ago and the managing agent moves VERY slowly.