Send in the gralat pack which you can see in your payment of your email, or your credit card.
I don't know but I think you can contact your bank or credit card (insert right word) and let them get you a copy of the receipt, if you're a kid like me I would mostly just ask my mom to get a refund it's easier and save more time about complaining.
I mostly had problems with purchases either getting multiple purchases (before I had a very big bug which caused my mom tons of ****load money.) but we've gotten a refund by contacting apple, or did my mom contact the bank I don't know but her bank account was like bankrupted status at that point but I didn't know what happened.
SOOO I suggest doing what my mom did would take 2 days but I prefer talking to apple or someone, not just toonslab trust me It was faster.
- edit: that's why my mom suggested me on buying iTunes card on my own apple account.