Call blocker might be of some help. Also don't pick up on numbers you do not recognize, or where there are caller IDs that seem odd. Or where there is no caller ID. There’s no way to stop the calls from being initiated.
I'm not sure it's mandatory telephones must be answered in any way. If you're able to miss calls, let unknown numbers ring and ring with no answer at all. They might call you, but there's got to be an answer of some sort for the caller to have a chance to say anything. Don't think threatening the handset or computer will do much good.
It's the IRS scam call that they are filing a lawsuit against you. Very bad english spoken. Saying that I need to get a lawyer or I will be arrested in 1 hour. Don't believe a word they say and never give any personal information.