R3200-00 to fix crack windscreen !

first car rental claim they dont have there own insurance for windscreens, so my windscreen on my hired car got cracked and they charging R3200-00 to fix !! , now i think they have car insurance and are covered for windscreen, so i dont mind paying that excess but the full 3200 WOW, how stupid, get some insurance.... but if i paid R25 and ticked that windscreen cover then they told me there insurance would pay..... something not adding up here...... so if i tick the box, then does the operator quickly phone there insurance broker and add the windscreen on ?