The power of telephone interview skills?

The telephone is just a communication tool. Many things can't be said clearly on the phone, and may also involve the issue of integrity. Generally speaking, nothing can be done without people.

How to confirm that the appointment will not be cancelled?

Establish effective communication methods, such as making an appointment to talk through SMS. If you don't reply, it can be regarded as cancellation.

Without being canceled?

This is actually very difficult. The veto is in the hands of others, but the chances of success can be increased by increasing the temptation and emphasizing the importance of the talks.