They claimed to be from ERG national research. I hung up.

Probably somebody calling on behalf of that smug little dipstick Bad Wall. They just hang up and can't be bothered to actually talk to you, it's very annoying,....just like Brad!

They left no message or name on display.

Hust hung up. Wouldn't leave a message. No name on display.

They hung up as soon as I answered.  Hello?....silence, click.