In-app purchases! HELP!

So a while ago i purchased about $11 on in-app purchases (episodes) for Surviving High School (free version) and then the app got accidently deleted. I have tried to download them again, but it will not let me unless I purchase them, and I still have the reciept on which it shows I purchased them. I am trying to figure/find out how to get them back without purchasing them again because the prices have gone up.