Expand your message with 'We're sorry we couldn't take your call this time.' The inclusion of 'this time' or 'on this occasion' suggests that the voicemail is the exception rather than the rule.
Phone system attachment to third-party services allows for transfer of data from one web-based location to another. Voicemail-to-text transcripts are one example of the type of data that businesses can capture and process at will. The audio of voicemail messages, saved as files, are also easily movable.

One of the chief considerations in recording an answering machine greeting is your audience. Who will be listening to your answering machine or voicemail salutation? Is this a business line or a home phone line? Furthermore, just how much information do you want to give out to potential strangers, like telemarketers, who may be calling your home? Long answering machine greetings may be inconvenient for callers.
Remember to watch out for ambient noise on your end of the call as well. Train signals, traffic, or even outside conversations can be very distracting to your callers and project an unprofessional image. Don’t forget the beep. Every millisecond – yes, millisecond – between the end of your greeting and the beep is time callers could potentially drop the call. That’s why the anticipated beep should sound the moment your greeting is finished. Leaving lengthy, silent gaps may cause your customers to wonder if they’ve been disconnected. Don’t give them the opportunity to hang up waiting to hear that affirmative tone. Check and then recheck your greeting. After you complete your outgoing voicemail message, play it back to verify you’ve said everything you intended to say. Then take it a step further and dial in to experience the greeting for yourself, and be mindful to contemplate the greeting from the customer’s perspective.