You have reached the voice mail box of (your name). If you’re a hot chick/guy, you may leave a message at the tone. If your one of (your name)’s friends, you may also leave a message at the tone. If you’re not hot and not one of (your name)’s friends, call back when you are. Hello. I’m sorry I didn’t answer your call.
Having said all of this, I do admit that I too use voicemail and have been guilty of switching my phone to the out-of-office assistant while I was sitting at my desk because I was in a conversation with someone or was in the middle of a project.

The basic rule of thumb is that callers should hear one of two things when they first connect with your voicemail — either an apology for not being able to answer the call or a “thank you” for having called. You can do both if you prefer, but keep it short and to the point.
check words for the English /oʊ/ vowel. Many non-native speakers make this more like a single vowel and it’s a double vowel so it should have /o/ and /ʊ/ smoothly joined together. Check it in the word ‘phone’ . Another double vowel to look out for in your Voicemail Greeting example is the diphthong vowel /eɪ/. This vowel is in words like ‘wait’ and ‘able’. Many people use the word ‘can’t’ in their Voicemail greeting example. This can be a trap for non-native English speakers. That’s why we chose ‘unable’ instead! Watch out for the word ‘can’t’! In American English and British English the vowel in ‘can’t’ is pronounced with the vowel /æ/ like in ‘pat’ – /kænt/.