Some people enjoy being very rude to such callers to get rid of them, some are more polite but end the conversation quickly but many keep talking, either not understanding that it’s a bad idea to talk to such callers and a waste of your time or are just too polite to end the conversation.
A more efficient approach is to be direct.
They will try to engage you in conversation “How are you today”? or a similar question.
Do not engage. If asked your name or to confirm your name – Do not engage.
Ask “What do you want”?
If not answered, then repeat the question until you get an answer or just put the phone down.
Once answered, you have the choice to continue the conversation or end the call.
End the call with “Goodbye and don’t ever call again” and put the phone down.
If you have a more effective approach then do let me know.