Ive been saving my grandmothers voicemails for almost 8 years now and when i went to upgrade my phone, i almost fainted when the rep told me they were going to be erased. Thanksfully he put us in touch with a company called http://www.voicemailsforever.com and they ended up much cheaper than the one you suggested above. i think your readers would benefit because they do it for so much less.
If you want to add another condition to your rule, select Add condition. You can add multiple conditions to a rule but do this judiciously so your rules don't become overly complex.

Once the voicemail is done, click the "Stop" button at the bottom part of the tool. You can find the recorded audio by clicking the three parallel bars at the right bottom of the recorder. From there, select the recording track and click the "Play" button to listen to the recorded voicemail. You can also click the "Folder" icon at the rightmost part of the Recording List section to open its output folder.
A voicemail greeting is a simple message that plays before callers leave a message. It may play either when you don’t answer or if your phone is off. A professional greeting may encourage people to leave messages, which in turn makes it easier for you to get back in touch. Keeping that communication open and efficient may lead to better business relationships. It also helps you put forth a professional image for your business.