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.
Hello, you have reached X (service provider). Unfortunately, all our agents are engaged in talking to other customers. You can stay online or to resolve something urgent, try our live chat service. You also have the option of leaving your name, ID and number and our agents will revert to you at the earliest.

Hello, you have reached the food delivery services of X. I am currently speaking to a customer and will not be able to take your call now. If you want some urgent delivery of food items, you can call our other number Y and place your order. Otherwise, kindly leave your details like your name, contact number and your order details so that I can get back to you for confirmation. Thanks for your cooperation.
Use your judgment to choose times that will be best for them based on what you know to be true about their industry and work environment.