the person just hang up the phone

no message left

given I got 3 calls from them yesterday but they wouldn't leave a message, I'm pretty sure that it's a robocall and bound to be a scam or political spam

NO message

Caller: energy rebate or something?

called 3 times today, first time didn't leave a voicemail.. second time i answered and they were claiming they're from energy rebate or something?... i told them not to call me again ...
but within 30mins they called again, still didn't leave a voicemail.
My theory is.. if they're legit, they will leave a voicemail.
I've now blocked the number.

Calls regularly. Answer phone responds so they just hang up. Absolute pests.

Keeps hanging up