In order to automatically direct a specific caller to your voicemail without your phone ringing, you’ll have to use a different method depending on which phone you’re using.
A busy greeting should tell callers that your phone lines are currently in use. You can direct people to wait on hold or leave a message. For example, “Hello, you’ve reached [company name]. Our representatives are currently helping other customers. Please stay on the line to speak with the next available team member, or press one to leave a message and we’ll call you back.”

Businesses should have two main types of greetings to create an excellent call experience. The first one is what we call a “welcome greeting” – this greeting welcomes callers to your business. Typically, a welcome greeting will present a menu of call options like hours, location, or customer service. For more details on how to create a welcome greeting for your general business number, read this article.
2. Enter the destination you wish to transfer the call to, then press [SEND] softkey. 3. Once the receiving party answers, announce the call. 4. To complete the transfer, press again. If you hang up before the call rings, the transfer will fail and the call will be disconnected. Direct to Voicemail: Transfer a call directly to voicemail 1. Press . 2. If a phone rings once and then goes to voicemail or rings only briefly, it You can't definitively know the cause of a phone barely ringing and going to voicemail because neither a phone company nor the phone's operating system provider will tell you if your phone number is blocked.