My wife and I both recently discovered there was a select few of our contacts missing on our iPhone4. I think 5 or 6 from mine and over 30 from hers. This happened a day or so apart. Neither of us have done iCloud or synced with contacts or any of that. The contacts just went away. Starting a text and typing in the first few letters does not work for this. The contacts are gone.
What may have caused losing 5-30 of our two iPhone4's contacts without using iCloud or any other sync?