Only takes once! I have an free app on my cell called "mr number".(mn)
Thanks to your info and confirmation that this is a caller I don't want to be bothered by, I entered this caller in my call blocking list. Now I dump them before they dump me (phone doesn't ring) and "mn" tracks the call attempts for me.
I will have data to file my complaint with the FCC (which will do no good but will make me feel better!).