Your message is a period of time that they are forced to wait through in order to do what they called to do in the first place — relay information to you.
Shawn Hakl is head of new products for Verizon's business division. Before the digital era, he says more than 80 percent of business lines had voice mail. Now, he estimates only a third of office phones have it.

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.
If you’re going to be out of the office on holidays or vacations, make that known in your voicemail so customers don’t think they’re getting ignored. Nothing is more frustrating to a customer than when they can’t reach you and assume you’re ignoring them.