L.J. -
Is this issue happening on your landline?
If so....have you ever considered getting a Magic Jack?
$50 to purchase device which includes your first year of service.
Then after the first year it's $40 per year to maintain service.
But the best part is their telemarketing screening option - when selected the caller gets a message saying they need to press one more digit in order for the call to get through. I use this option and can tell you it has eliminated 100% of all telemarket/robo calls for me.
But I do get calls from those I do want to hear from.
It's truly remarkable for that purpose and on top is very cost effective.
https://www.magicjack.com/
Good luck!