Please help with my simple queroy!

Happy Saint paddys day!

I'm new to the web site and a little bit of a novice at excel, so this looked like a friendly place to ask my noobish questions!

I am keeping track of people I'm calling by company and phone number and am looking for a way not to call the same company twice. One way I think I can do this is to auto sort column A alphabetically. This way things a business that comes up right away will be obvious. I've tried using the duplicate values setting that comes with office 2007 but it doesn't seem to do it automatically. Any suggestions?