Repurchasing an app I refunded?

Hi all,
In November 2014, I purchased KNFB reader. At the time, I had an iPod touch 5, and was very unhappy with the app’s performance on that device. Soon after, I got a refund because I did not want to waist $100 on an app that didn’t work for me. Since then, I got the new iPod touch 6, and just got the iPhone 6s. Now that I have a device with a much better camera, I want to repurchase the app. However, when i try to do it, I am told that the download is unavailable because the app was refunded or canceled. This happens after I click buy. Does anyone know if there is anything I can do to repurchase this app?I really want to purchase the app again, and I am really annoyed that apple won’t let me purchase it again. Has anyone else ran in to this situation, and Have you found a way to repurchase the app? If I have to, I will see if someone can gift it to me and pay them back for it.
Thanks