Only Basic and Premium Plan has support options. There will be no support for starter plan. Once your app is live functioning well, your support ends in starter plan.
You can contact asap after paying if you want refund. But once we have started working on App there will be no refund.
There will be no changes or modification on starter plan. And app updates depend on plan you select. App will be updated with new features that are essential.
For Starter and Basic plan, your app will be ready in 48 hours and will be submitted to App store. Time for becoming live depends on App Store approval timeline.