Very Simple Twilio iOS App

We are looking for a developer to code a very simple Twilio iOS App. Twilio has an iOS SDK and quickstart. Should make this very easy. You should be familiar with iOS apps and Twilio. The app should work as follows.

1. User installs app from App store
2. User enters the 10 digit number they want to receive calls on (we would provide them this information) then click GO. If not an approved number, the app says, "Invalid Number".
3. Calls to that number (which is hosted on Twilio platform) are sent to that iOS app user.
4. Using Apple PushKit the call is sent to the app. The caller ID name and phone number is show to the app and on the notification of the incoming call.
5. Must use CallKit framework.
6. User can use phone, speaker, or any bluetooth to handle the call.
7. End the call with END button.
8. No outgoing calls/no dialer/keypad.
9. If user is already on a cellular call or another call, they must be able to HOLD & Accept the Twilio call.
10. If user is already on Twilio call, they must be able to HOLD & Accept any other calls (including another Twilio) call.
11. To change #, they click LOGOUT.