Mike, I'm 99% sure those are spam calls.
I just answered my phone two minutes ago, it was someone with a thick accent asking if I was the one who had back pain. I asked what he wanted and he said they were conducting a survey to find people who had pain in their back or pain in their knees. I said I had a pain in the a$$ and he was on my phone. _CLICK_
Regards, Neil Tucson, AZ