First, you definitely won't need to pay again. This usually happens when you switch phones, or restore from a backup. Getting the premium features to you is pretty easy.
- Just tap the clock on the main screen (bottom right). It will bring up the purchase screen.
- In the lower left you'll see "Restore". Tap that.
- Give Apple your iTunes login, you won't be charged for anything.
- When it's done, it should unlock everything for you.
If that doesn't work, contact support and we'll get you to the next step.