I returned a call from (03) 8521 4998 but the voicemail didn't mention the company name

Person with Indian accent trying to sell/discuss electricity rates.
Really annoying.

Caller: Off Bargain? Something about electrivity rates

Received two calls from these people today, trying to discuss electricity rates. Refused to remove my number off the contact list, despite being told previously. Said they did not have the power, but if I listened to him he would never call again. I told him to note that I had heard what he said, but wanted no further contact and disconnected. Was also calling from a foreign call centre using local Caller ID. (I work for a call centre and know the sounds of an outgoing call from a call centre).

Caller: "Offer bargain" electricity

Called twice, silence the first time, stated they were "Offer bargain" calling about "electricity" the second time when questioned.