have you got areceipt for the purchase that does not look real?

Greetings,
Yesterday I received an email with a receipt for the purchase of the -Alfred Huang-Themes Guru - LockScreen Themes & Wallpapers with Creative, v1.1 (4+) for $ 16, I have the wallpaper app but I did not buy anything In addition, the receipt I received is very different from the receipts I usually get ,it didn't have my details and did not have the address of the apple on it, The receipt does not look original.how will I know if it's real or not?

Best regards