If you previously did not allow Punchbowl access to your iPhone Contacts, you can allow access from the Settings menu on your phone.
1. Open "Settings"
2. Scroll down to the Apps and tap "Punchbowl".
3. Tap the Contacts toggle to give Punchbowl access to the Contacts on your iPhone
4. Now open the Punchbowl App and you will see your Contacts on the Add Guests screen.