Hello Parichat, Its Kishore again from iTunes Store Customer Support team. I hope you are having a nice day! I wanted to follow up with you about your concern.
You should receive your refund within ten business days. If you have any questions, let me know. I’ll be happy to help. Note: If you haven't received the email which was sent by me addressing your concern on “19-OCT-2015”. I've copied the previous email below. Sincerely,
Kishore
iTunes Store Customer Support
http://www.apple.com/support/itunes/ww/
Please note: I work on Sunday- Wednesday and Saturday 08.00 AM to 05.00 PM CST.