For those who bought tickets through TicketOne, there is a process to follow in order to get your money back.
If you order on line, look for the heading TICKETS TO CANCELLED EVENT TICKETONE.IT OR CALL CENTER. Click where it says click here . That will lead you to a form to fill out. It's in Italian, but you can use Google translator or any other translator to figure out what it says.
We're lucky because I believe some concerts between March and May only allow people to get vouchers for future concerts, but we get our money back.