I said, way back in Post #7. "As Richard and Raymott, both native speakers, have suggested, there appears to be no specific term in English. I certainly can't think of one. " That's two speakers of BrE and one of AusE. Barb, a speaker of AmE, appears to have joined us.
It may well be that Indian English has expressions for this, but unless somebody who knows writes in, I think we'll have to accept that we haven't in those first three dialects.
We can make suggestions till the cows come home, but they are of little value unless we know that people actually use them.
NOT A TEACHER.
For no. 2, "to cut someone off" might work.
I don't know a specific phrase for the first situation, but for the second I would say I ignored the call. In fact, my phone gives the option to answer or ignore a call.