A free program for Android, by Dzine Media Apps.

WAMR: Recover Deleted Messages is a free app for Android devices. This application has been designed to recover recently deleted messages, photos, videos, and audio files from your device. If you are looking for a way to restore the most recently deleted messages from your WhatsApp account, then this app is for you. This app will work for you even if you are using a dual SIM device or have lost one of your SIM cards.

The process of recovering removed chats is quite simple and easy to use.