Unlike other councils, voting is compulsory in Melbourne City Council elections (including by-elections) for everyone enrolled on the Melbourne City Council voters' roll, except in special circumstances laid out in section 119 of the Local Government (Electoral) Regulations 2016. If you don’t vote, you risk a fine.
If you’re one of two company representatives eligible to vote and you, the other representative or both of you fail to vote in the elections, the corporation is guilty of the offence, not you as the representatives.