"They called and hung up." What this mean is they were using an auto-dialer that dials five numbers and the same time. The first mammal that picks up on the phone gets routed to the operator and all the other four calls are the familiar "nobody's there". A computer hung up, not a human. This might be helpful for the other 10 calls you get during the day.
This one was EHSD which is some kind of pimping service that is purportedly leveraging California state energy laws to sell you, I assume, solar panels. After listening for almost two minutes I tried to tell him I didn't want to waste his time, no, I wasn't interested, etc. He eventually hung up saying "Another operator will be able to explain it better" and hung up. Indicating they will call back.
Note that I have put a call block on "EHSD" but the CHANGE THEIR NUMBER CONSTANTLY!
I have this number on my cell# reject list. These idiots call almost daily...day and night. They also use the same # with last two digits as"45". ENOUGH!!!