I booked two tickets for the Colosseum today, but my visit date is in January 2016. The tickets are nonrefundable, and I cannot change the dates on it since their policy is that the tickets purchased this year must be used by Dec. 31, 2015. I should've read the instruction carefully before proceeding, regrets, regrets and regrets.
update: I have been informed that the tickets are valid in Jan.!
Thank you all for your advice!!