Insuring your tickets is possible in the second step of your online order*. With a cancellation insurance you can get a full refund if you are not able to visit the event due to an insured situation, like illness, death, etc.
Unfortunately, it is not possible to insure your tickets when booking by phone. You can then take out insurance afterwards. See Can I add cancelation insurance after completing the order? for more information.
*The cancelation insurance can only be purchased by residents of the Netherlands. It is not possible to use the insurance if you live abroad.