A voicemail greeting, on the other hand, refers to the message that your callers hear upon answering the phone. Voicemail greetings can include any information you’d wish to convey, such as special sales, bargains, alternate phone numbers to use, or your company’s normal working hours.
In the former, the voicemail message shall be delivered to callers from within your company i.e. for communication exclusively for office employees. In the second case, the voicemail will be received by people calling from outside the company. Hi. You’ve reached Martha Johnson in Human Resource department. Unfortunately, I cannot attend the call now. You can leave your message after the beep. Hello. You’ve reached Martha Johnson in Human Resource department. You can either record your message after the beep or contact my secretary Henry Smith at extension 5556. I shall get back to you soon.

A professional voicemail greeting should be no longer than 60 seconds. List the important information we've discussed above, provide alternative methods of communication and close with a thank you.
There is no need for a voicemail message to convey this, unless the therapist conveyed false expectations in the first place. I used to tune out those “call 911” messages.