Video: How to Restore an In-App Purchase on your iPhone
If you've done an in-app purchase and you don't see that purchase as having gone through, one thing you may need to do is restore. And I've got that experience right now with this app "I-conv" which was free, and then I had to pay $5 to make it work on a regular basis. So what I need to do is go into the app. And this will be different, a little bit different for each app, but you'll go to the settings for that app.
And then here I click "upgrade to pro $5." And I get this screen where it says to restore purchase or upgrade. And I've already upgraded so now I need to restore purchase. Restored successfully and now the app will work as if it's been upgraded. And you can see if you go into the iTunes store on your account, you can look at what things you've purchased to see if the purchases are in your account. And you might need to contact the developer if that doesn't work. But this is the simple way to do it. And hopefully that works for you..