3. Push the asterisk (*) or pound (#) key and then press the call button to call your voicemail. In some cases, you might not need to press the call button but you usually will have to listen to an automated greeting before you can hear your voicemail. Check to make sure that the asterisk or the pound keys are the correct buttons to press. Which key to press and when to push can depend on your cell phone provider. For most cell phone companies, it's often one of these buttons. Try both, and if neither of them work than visit the website of your phone company or call customer service.
Thank you for calling {insert company name}. Please choose from the following options: If you’d like to speak with the operator, press 0. For customer service, press 1. For the sales department, press 2. For accounts payable, press 3. To listen to our staff directory, press 4. To leave us a voicemail message, press 5. Press 6 if you’d like us to repeat this menu. 4. When they call outside of business hours.

In my (US-based) experience, doctor offices & the like have a place where you can fill out if they can leave messages or not (and some even have asked detailed messages vs callback messages), so that's my perspective! And that I can set different things for different numbers. So my cell phone they can leave detailed messages on any matter, my mother's house phone is detailed from billing only and otherwise callback, her cell phone is callback only. (And they also aren't allowed to tell her anything other than billing, so even if she does call them back about anything else! That was just a measure set up when I lived with her one summer & had no cell reception at her house.)
– Thank you for calling (name of the company). If you know the extension number of the person you are trying to reach, you may dial it now. Press 1 for sales. Press 2 for customer service. Press 3 for the billing department. Press 8 to access our fax on-demand system. Press 9 for a company directory, or press 0 for the operator.