My former employer (over 2 years now) is suing me for hacking. They let me keep the iPhone which pings their Exchange server to AutoSync.

This sounds like there is some confusion on BOTH sides. What the employer believe is "hacking" is likely some continued use by you of the iPhone to sync to some dataset that presumably you have been tapping into or accessing for some claimed insidious reason. The employer is claiming hacking because they (a) may not be aware of the means through which you have been accessing the information or (b) are relying in the "unauthorized access" aspect of the conduct since you could have easily stopped the autosync. That all stated,  if you are being siued you need to retain a lawyer IMMEDIATELY to get this issue under control and focus on the REAL issues giving rise to the lawsuit and not distractive ones like "they lied to get a warrant" which doesnt even exist in a civil case. Be prepared to spend a good bit on such a case if there is "bad blood" between you and the ex-employer, especially if they are committed to seeing the law suit through.