Probably time to obtain a call blocker device, app, or phone.
Google "call blocker" to see the various types, and find one that best meets your needs.

Person barely spoke English and said they were from the "Vehicle Processing Department". When I asked what the name of his company was he said that was the name of the company and when I asked what vehicle he wouldn't say unless I verified who I was, which I wouldn't do.  I hung up and blocked the number.