Solution: Poor sound quality is unlikely the fault of a reliable business voicemail service that uses VoIP technology, Baldwin says. So garbled voicemails are often due to callers’ poor mobile phone reception while leaving their message—and you may just need to call them back, assuming you can figure out their phone number. But if the problem does seem to be your voicemail, make sure you’re using a business phone and voicemail service that uses VoIP and not relying on, say, your mobile phone’s voice mailbox.
Verbal Content – generally, you should use 100 words to make up 1 minute of content produced with background music. In other words, one to two paragraphs per minute. The topic can range from product promotions to general company information.

4. Vacation Day Voicemail Greeting. If your business is off for a holiday, it's a common courtesy to update your voicemail to acknowledge the closure. Mention the closure in the beginning of the message, convey when your business is reopening, and don't forget to wish the callers a happy holiday if the occasion calls for it.
Some people may be uncomfortable leaving voicemails and will hang up instead. You don’t want to lose customers simply because they don’t want to leave messages.