DD (15)'s friend bought her a ticket to a 'meet the celebrity' type event for her birthday (£30) about a month ago, friend did check beforehand it was ok. Last week something came up which means DD can no longer go, event was 2 weeks away at that point. DD told her friend and gave her the ticket back, friend has now asked her to pay for it as she can't find someone else to go. AIBU to not pay friend for ticket or should I just pay?