We also have a landline to the house (in addition to cell phones). This is mostly for old aunts & relatives who don't have cell-phones & think we pay extra if they call ours. About every 8-9 solicitor/scammer that calls receives a return call.
I tell them I'm coming to their office armed & will shove a shotgun barrel up their azz & blow their brains out. I bait the "IRS" agents, pretending to be concerned - & then ask them the jail time for slitting their throats & raping their dead carcass. I am extremely vile & vulgar with women, asking them if they are lesbians or are currently servicing their male bosses - & the men are asked if their bosses regularly sodomize them over their desks.
Lately it's been Student Loan consolidation calls on my cell - same treatment: Press 5 (more info), & berate them.
I have to be in the right mood & always apologize if I've mistakenly expressed these things to a missionary, pastor or church choir director.