1. I have been trying to call you. (is used when the action is still on). Yes. This means "I have tried to call you and I am still trying to call you."

Has been trying or have been trying?

He has been trying , which is a present perfect continuous, and he has tried , which is the present perfect tense, do have a slight difference, and present perfect continuous is often used by native speakers to stress certain feelings.

Will have been trying tense?

The future perfect continuous, also sometimes called the future perfect progressive, is a verb tense that describes actions that will continue up until a point in the future. The future perfect continuous consists of will + have + been + the verb's present participle (verb root + -ing).