The trouble is how to hit back at them. Normally the most that you can do is to waste their time & phone bill -- but your time is more precious than that. I wanted to try to get some of them to stop scamming and, to a limited extent, succeeded.
I had a phone call from one of these crooks claiming to be from Microsoft security center trying to tell me about a problem on my MS Windows machine (I run 100% Linux). After a few seconds I interrupted him and asked him if he was a religious man. He was puzzled and, after a couple of prompts, said 'yes'.
I told him that I was worried about his eternal soul ending up burning in the fires of hell because he was trying to steal money from people while he was alive. I asked if it was really worth it spending billions of years burning in hell for the sake of making some money in the few short years that he is alive. None of us is alive for many years compared to the billions of years in heaven or hell after we die.
I asked him to think about it before he went to sleep tonight. Where did he want to spend eternity ? Should he be doing the job that he is doing ? Is it worth it ? How will he be judged by God ? He was by now sounding a very different man from the one who started the 'phone call a few minutes earlier. Thanked me for being concerned about him. The call continued for another minute or so, me laying the eternity bit on very thick. Him getting quieter, before quietly thanking me again before the call ended.
I don't know what long term effect this will have on him, but hopefully he will decide that he ought to get another job. I did this a few times, some just laughed, then I got bored with the game.