refund for duplicate purchase?

I purchased an audiobook from itunes and when I went to download button, it said I had to connect to WiFi (which I am usually, but wasn't for some reason) and so I did (in settings) and I went back to 'downloads' and it wasn't there anymore. I waited a few minutes, and ckd again, and it was not there still. So, I wen to 'purchase' it again (like 4 min later), figuring it would say 'you have already purchased this" and it didn't and repurchased it. I went to 'downloads' and there it was with the first one!

Any number to call to ask for a refund? I might not have done it on an app or a song, but a $ 25 audiobook, I will..

thanks