Epic Quest in app purchase unable to restore in iPad mini

[Mikengo]

I've just purchased Epic Quest. I'm able to download in my iPhone 5 but nothing's happening on my iPad mini. When I click restore app in my ipad Mini, a password prompt popped up and I entered accordingly. Nothing happens after that. However, on the iPhone it has a download bar with % completion. Am I missing anything in my iPad Mini?

Thanks in advance for the advice.