Recording a Voicemail greeting is hard!

Phone - needs to now how to set up voicemail
client is at home
Accessing Voicemail from an External Phone 
Client received instructions in his email:
From an external phone call: 1800voicemail
Anytime during the greeting dial #
Dial the 10 digit extension of the voicemail you wish to check followed by # when prompted
Dial your passcode followed by # (default is 123456)


client wants to change the greeting
had him listen to the voicemail options for greeting options
he is unable to, he keeps talking over me and the voicemail instructions
I called the voicemail number and I can hear the instructions just fine
immediately it asks to set up voicemail 
it says hit star to record a greeting and # to skip
told client to hit star when it says to record the greeting 
client still doesn't understand how to record a greeting
explained to him several times
he called the voicemail while he was on the phone to me but he was talking over the instructions
he asked me to record his greeting, due to security I can not 
advised to hang up with me and carefully listen to the instructions