Good for you for making the effort! He deserves to hear from the shareholders he has disrespected (and maybe worse). Your experience was a bit different from mine (from a few months ago). The switchboard did put me through to his extension. A few times it did go to voice mail, but on two occasions, I did reach him.
In hindsight, kind of funny. First conversation, he let me do all the talking while he just made noises like he didn't know what I was about. Only after the call, did it dawn on me that I had been played. He had not actually denied anything. Second call I pressed for clear denial or confirmation, at which point he got flustered and hung up.
He does have a function at Assurant, so must interact with people over the phone. I suspect that if you are persistent, you will eventually get through.
May I say that I am impressed and pleased to see a shareholder not taking this crap lying down. Best of luck.