If you have no backup for your chat history you can download iPhone data recovery software in order to overcome the problem and restore iPhone chat history loss. Still you have not recovered lost whatsapp chat history from iPhone, some on-line applications also available which can be helpful in restoring precious contents details, probably will be able to find the solution to some extent.

iPhone 6 Data Recovery is a powerful recovery tool which enables you to recover deleted or lost data files from iPhone directly or extract to recover from iTunes /iCloud backup file easily and quickly. It’s the world’s 1st data recovery software for iOS users to recover lost data including Contacts, SMS, Photo, Video, Notes, Call history and more from iPhone, iPad & iPod touch.
You can recover deleted contacts from iPhone, all you need is a data recovery for iPhone data recovery,on the market, few data recovery software supports recover contacts from ios iPhone 6 .Now,I recommend you a professional data recovery,which supports restore contacts from iPhone 6.
If you fail to get your lost pictures directly from your iPhone, or your iPhone type is 5S/5C/5/4S, you can extract the iTunes backup. But before this, what you need to do is that synce your iPhone with iTunes before you lost those pictures.

Step 1 Choose and Extract the iTunes Backup

Choose “Recover from iTunes Backup File” option, when launching the program on your computer. Then, you’ll get the interface below. Choose the latest iTunes backup of your iPhone, and click “Start Scan”.
Step 2 Preview and Recover your iPhone Photos

Being scanned, all founded data are in order. After scanning, you should preview carefully to choose those you want and click “Recover” button to save them on your PC.
see more:
Recover Deleted SMS from iPhone 6
Recover Lost Data from iPhone
Recover lost contact from iPhone 6
recover deleted SMS messages from iPhone 6/5/4S/4/3GS?

 

If you have made a iTunes backup before, you can connect your iPhone to iTunes, right-click on your device and select the backup to restore, else you can use iPhone 6 data recovery, it not only can extract iTunes/iCloud backup, but also can directly scan your phone and recover lost contacts from iPhone 6, just need 3 simply step.

 

Many situactions may case the iPhone data loss, you may delete it by accidentally, system crash, forget password, damage your device or more, if you create a backup before, you can restore whole back to iPhone via iTunes or iCloud, but you will lost all old data, so you can try the iPhone file recovery tool to extract iTunes/iCloud backup, it also support to recover from iPhone directly.
how to recover lost contacts on iPhone
how to recover lost text messages on iPhone

 

I think you need to use iPhone Data Recovery. It can scan your iPhone deeply to find the lost contacts for you. You can preview the details of the lost contacts and then recover any of them from your iPhone 6 to computer. Learn how to restore lost contacts from iPhone. Besides contacts, you can also recover messages, photos, videos, call history, notes, reminders, calendars, voice memos, voicemail, safari bookmarks and other deleted data from your iPhone 6 to computer.