When you publish your survey to the Feedbackly iPad app, you will likely want to lock the iPad so that customers cannot exit the app. This is very easy to set up and only takes a few minutes. Using the guided access feature in iOS, you can disable every shortcut that is used to exit apps, including the home button.
Step 1: Download the Feedbackly App
Step 2: Publish your survey to the app (Find instructions on how to do that here)
Step 3: In the iOS Settings menu, select General
Step 4: Select Accessibility
Step 5: Turn on guided access
Step 6: Open the Feedbackly app
Step 7: Triple click the home button
Step 8: Click 'start', set your passcode and you're done!
If you want to exit the app, just triple click the home button and type in your passcode.