Entries from the visitor list cannot be deleted, with the exception of users who you block. These users are hidden from all lists.
How can I retrieve a deleted chat history?
- Open the profile of the user whose chat history you wish to retrieve. You can find the user by entering his/her name in Search or by locating him/her in the visitor/Faces list.
- Open the Chat with the contact via the chat symbol in the action menu on the bottom right.
- Open the options menu on the top right and click “reload”. The chat history will now be synchronized and old messages will be retrieved.
How can I block a user? - https://support.choiceoflove.com/hc/en-us/articles/201648791