How to prepare a questionnaire regarding the customer satisfaction on Apple iPhone?

Here are some questions you might ask: 1) How long have you had your iphone? 2) How long did it take you to figure out the primary functions of your iphone? 3) Do you plan to get a new phone at the end of your contract? If so, will it be another iphone? 4) Do you find the iphone easy to use? 5) What made you decide to purchase your iphone? 6) What is your favorite feature on your iphone? 7) What is your least favorite feature on your iphone? 8) if you could change anything about the iphone what would it be?