Since I pride myself in being responsible, if I don’t receive a return call I have to assume I wrote down wrong number. If I were irresponsible I would just blow it off and not care. But if I wrote down the wrong number I have a responsibility to get a hold of this person. This extra work combined with wondering if it’s the right number, leaves a bad taste in my mouth.
Be unique in your voicemail greetings, add a human touch when creating the message.

“Hi, you’ve reached [XYZ Company]. We can’t take your call right now but feel free to call back during business hours from [hour] to [hour], Monday through Friday. In case of an urgent query, you can contact us through our website [URL] and access our live chat.
It might be a short voicemail message that you’re recording, but you do want to make sure you hit all the bullet points. It also helps to speak eloquently over the phone and that works better when you are prepared with what you’re about to say. You are trying to sell yourself in this message so put your best foot forward. If you practice and write down what you’re going to say, you can get rid of all the awkward pauses, ums, and stumbling over words.