Spam callers have basically ruined telephone as a medium. For many, a phone call is more likely to be fake and spam than it is to be legitimate. And even if the call claims to come from a source you might trust, good odds it's spoofed and thus cannot in fact be trusted.
A shame on telecoms for not being willing to tackle the problem.
Plus addressing (your-email+somearbitrarytag@domain.com) is also a nice tool at your disposal. Helps track where the spam is coming from. I've found few/none trim it when storing addresses so it consistently works.
Job hunting is the worst. I have to answer every single call for a while knowing full well it's probably a telemarketer but not having any other choice.