Deleting btinternet mail account from iPhone has deleted all the emails on btinternet server

Yesterday I deleted a btinternet mail account from my iPhone but doing so has deleted all the emails on the btinternet server. The entire email history on all folders has gone and when I log in to the account through the web page they are all gone. Is there anything that can be done? I have done this before with hotmail account but it didn’t delete the emails at source. I think this is a bug, perhaps specific to btinternet. I am on the latest iOS version 16.5.1. Any advice appreciated as I’m desperate to try and get the emails back