Friends and colleagues speak to each using first names only. So do people of authority. They do not call each other and leave voicemail messages asking for Mister, Miss, or Mrs. Therefore, when you call a person you want to do business with and you leave a voicemail message, refer to them by their first name only. Don't say mister, miss, or misses. Don't say their last name. Begin your voicemail message by saying only "hi/hello" followed by the person's first name. Or, you can even forget the "hi/hello" and just say the person's first name. That is how you show confidence and authority and separate yourself from weak salespeople.
2. Hello, you have reached the office of [your name]; I will be out of my office starting on [date] and will be returning on [date]. You can call me when I return or leave a brief message. If this is an emergency I can be reached on my cell, which is [your number].

There is no definitive answer here, but you should include one of the two at the beginning of your message based on what makes the most sense.
1.) Bem-vindo à John Doe. Infelizmente, não há ninguém no escritório agora ou você está ligando fora do horário comercial. Por favor, deixe uma mensagem ou envie um e-mail para [email protected]. Muito obrigado pela sua ligação.