Caller: Scammer a hole

Called my mums phone and left a voicemail with talking in background I called the number on my phone and didn’t go through call couldn’t be connected so a scammer or a robo caller

keep calling back (at my work) trying to tell me about the new energy rises after the budget. they say they work for all the energy companies to inform their customers. I keep telling them ill deal with my company myself and they get very cranky so i hang up. they continue to call back asking for me. Not sure what the scam is