Phantom Call

It may happen to everyone to receive the phantom call once in a while.
I am not sure if it is appropriate to call 'it' the phantom call. But the situation is like this, you pick up a phone call, either the call is unidentified or the number is blocked, the caller hangs up right after you answer it. It annoys people, particular me !
I don't know how people react to this, but if you were once harrassed by this sort of calls. You don't feel that it's easy to get over the unpleasant feeling.
I was once harrassed by the phantom calls, the time lasted for on and off, like....4 years.
The worst time, I would receive it almost every day. Of course, I knew who was the caller and tried many different methods to stop that. . The thing that confused me the most and never abled to get the answer was, What was the purpose? Was it fun? Or just to make sure I was still alive?
It bothered me for so long that left a shadow on me, and nowaday, I screen every call carefully.
The reason why I want to talk about this is because, after 2 years without answering this sort of call, I received the 'phantom call' again this afternoon. This time the number wasn't blocked, I called right back to see who the person was because the number look familiar and it wasn't in my caller list. Every time I change a new cell, I would re-arrange all the names in my phonebook, so I didn't want it to be one of my friends called and I missed it. However, the call transfered right to the voice mail box when I tried to reach. I told myself not to think too much but it seemed hauting me and bringing back the bad memory of me. The annoying phantom call~~~