You contact Allianz to cancel it as long as it's within 21 days of the booking. Ticketmaster is unable to cancel the policy for you and can't refund the amount to you, as the funds are already with Allianz. You can contact Allianz on 0345 641 9726, by email at email@example.com, or by writing to the address below:
Customer Services Manager
102 George Street
For theatre shows, you’ll need to contact Ticketplan. You can make a claim on the Ticketplan website.