Whatsapp chat backup not found in iCloud backup

I bought my brand new iPhone X and recovered all the data all right. My problem started when I had a problem with the camera autofocus. I went back to the apple store and they promptly gave a new Iphone, no questions. The only thing I had to do was recover all the data from the iCloud backup again. I started and everything was going fine until WhatsApp did not find any data. It just kept appearing that there was "no backup found". Does any had the same problem. I have a lot of importante chats and information in my WhatsApp , It is very important to me to recover that information. Thanks for the help in advance.