Are you as fed up with robo calls as I am?  If so, you may be interested in reading this article that explains how to minimize or possibly eliminate such calls:

https://www.cnet.com/how-to/block-people-from-calling-texting-emailing-your-iphone-ever-again/?ftag=CAD1acfa04&bhid=29048217186333403461582603301697&mid=12849676&cid=1874100215

I hope you find this information helpful.

Dwight