Recovering deleted chat messages can be difficult, especially if you don't have a backup. The specific method may vary depending on the chat app. However, you can try the following general methods: 1. **Data recovery software**: There are some professional data recovery tools that can help you scan the phone storage space and try to recover the deleted chat history. For example, iMobie's PhoneRescue, Tenorshare's UltData or Dr.Fone. 2. **Check the cache**: Some applications may still have some records in the cache. You can check before cleaning the cache to see if you can get it back. 3. **Contact the service provider**: Some chat app service providers may keep chat records on the server for a certain period of time. You can try to contact their customer service to ask if it is possible to recover them. 4. **File manager**: Use a file manager to check the residual files that may exist in the storage device to see if they contain chat records. Please note that using third-party tools may have the risk of data leakage and privacy issues. Be sure to choose trusted software and services and pay attention to personal privacy and data security. In addition, back up important data regularly to prevent similar problems from happening again.