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?

 

It's really easy to do that. You can try to use iPhone Data Recovery. It can scan your iPhone deeply to find the deleted contacts for you. You can preview them before recovering. Learn how to recover lost contacts from iPhone. Besides contacts, you can also recover text messages, photos, videos, call history, notes, reminders, calendars, voice memos, voicemail, safari bookmarks, Whatsapp messages and other deleted and lost data for you.