We believe that your chats are very important, and we work hard to make sure that you never lose them. However, in the case that they are deleted or lost for any reason, we cannot help you recover the messages because we do not store your WhatsApp chat history in our system.
At this time, there is no process to recover your deleted messages on Nokia S40.
To transfer your WhatsApp chats to another phone, read this article.
To learn about how to export your WhatsApp chats, read this article.
WhatsApp Support Team