It’s bad advice. Just stop answering the ones you don’t recognize. If you have android, Googles phone app is pretty good at giving you the name of the company that is calling you (assuming it’s not spoofed). It’s also pretty good at flagging calls and texts that might be spam. If you are waiting for a call from your mechanic for example, it will usually show you that its Firestone or NTB or whatever calling.
Stop answering spam calls and they will eventually go away. If they don’t go away or seem like they are waning, you might have someone fucking with you and it’s time for a new number that you don’t give out to anyone. I do the same with email. I have ProtonMail and I have a few aliases that I use for specific purposes, if/when one them is leaked/sold/traded/whatever, I will temporarily pause that address and eventually it will get flagged as a bad one and they will stop coming.