I apologize that you are unhappy with the app. A couple of notes:
1) The app in which the document you would like to convert must support "Open In". Many apps support this functionality, so you might ask support for the app you are opening from if there is such an option. Some apps use a square icon with an arrow to denote sharing rather than using the words "open in...".
2) When you choose "open in", the ipad only shows a few of the available options in the resulting popover. This popover is actually scrollable. If you have several apps that support viewing documents, it may be that Create PDF is scrolled to the bottom of the list. Please try scrolling.
3) We don't support every file type for conversion (the types are listed in the app store).
Could you please share the type of file that you are trying to open and the apps from which you have attempted to open?
If you would still would like a refund, you need to contact Apple through the iTunes "Report a Problem" feature.
Thanks for your question!