BB Bold 9700 :: Lost Contact Information - How To Retrieve?

I seem to have lost some contact information. Though many of my contacts are still intact, others no longer show a secondary phone number I once entered, or some contacts seem to have disappeared completely.The strange thing is, when I dial one of the "lost" numbers manually, the contact's name does show up! But I can't find it in the list of contacts. I have already checked and unchecked the Business and Personal options in the filter menu, but that didn't do the trick.Any suggestions on what I might be doing wrong?note: this problem is not my own - I'm asking for a friend of mine