Just called. After hearing no response to "Hello?" I finally got the "Your call is very important to us. Please stay on the line." recorded message before hanging up. Blocked.
Yep, just got a call from them, twice, within the past few minutes. No one ever replied to my "Hello?" inquiry. Likely some spammer, like the 214-509-6344 calls I had been getting for the past ~2 weeks, which I blocked. I'll block this one, too.