In Australian English it’s pronounced with the vowel /a:/ like in ‘part’. Problems arise when people use the /ʌ/ vowel (like in ‘up’) instead of /æ/ or /a:/. If you do this is will sound like the worst swear word in English. Many non-native speakers often pronounce the vowel /æ/ more like /ʌ/ because they don’t have a vowel like /æ/ in their first language. Many speakers of European languages will do this (Spanish speakers and Italian speakers) and also speakers of Japanese and Korean. This problem with /æ/ also means that if you say the word ‘back’ in your voicemail greeting sample, you are likely to pronounce it more like ‘buck’. remember to pronounce word endings in English. Check you aren’t dropping any endings off or mispronouncing them.
Sending an email to each prospect before you call gives them an additional way to get in touch with you when they're ready. As you're leaving your voicemail, mention that you've sent them a quick email as well that has further details on who you are and the purpose of your call. As Florin Tatulea of Loopio explains:

Sales reps tend to be very declarative in their messaging. Their starting phrase in both voicemails and emails usually sounds something like, "My name is John Doe, and I work for Gadgets Inc."
When using a Cisco phone, you can record and change your voicemail greeting directly on the phone. For the following instructions, to select an option, you can use the phone's blue toggle button to scroll down and highlight the desired option, and then press the Select soft key. Press the Services (globe icon) button on the phone.