Unfortunately, if your software automatically published the PC-resident phone contacts database to the iPhone, what was on the iPhone is gone. It's unfortunate that the software is sufficiently ignorant not to check dates before destroying data, but it operates based upon the dates of containers (folders and directories), not upon encoded (viz., in text) dates of individual messages, contacts, etc. Your only hope is if you purchased iCloud services and your iPhone contacts were previously automatically uploaded to a server managed by Apple. Otherwise, I'm afraid your out of luck. Please let me know whether you contracted with Apple for such iCloud backup services.