How can i get a refund my six year old purchased some software, we can't use software as we...

My six year recently had access to my account and purchased over two hundred pounds worth of games, i would like to get my money back without making a claim fraud against my son. He doesn't live with me and i let him use my account on his xbox 360 not
thinking that he could purchase games. I would like to know where i stand in regards to getting my money back. I have 3 accounts and he has access to all of them, i have now locked him out this one until resolve this matter

:)