Insurance company asking me for car insurance details or pay the amount stated.

I have just received a letter from the third party car insurance company to pay them substantial amount for the damage which has nothing to do with car accident or direct vandalism to cars.

The truth was I bought timers from B & Q when I cam out side the B & Q car park the cyclone occurred outside B & Q car park when heavy duty timber trolley belonging to B & Q was uplifted by the force of nature 10 ft high damaging cars and every thing in his path.

We have eye witnesses working in B & Q and video evidence surrounding car park to proof the incident.

Why should I be responsible for some thing got damaged by nature?