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.
Your voicemail service is usually controlled by your mobile carrier, therefore, the most reliable way to turn off your voicemail is to ask their support team to disable it:

For a downloadable Quick Reference Guide to the voicemail phone menu, click here.
While email and text support saw an increase in recent years, many customers, partners, and potential hires still prefer to call your company directly. When writing your voicemail script, include basic information such as a short greeting, your company name, an invitation to leave a short message, and the time frame in which the caller can expect a return call. If relevant, you may want to include your office hours, extensions for company departments, and the contact information for your office manager or HR department.