About every five or six months, hundreds of my deleted emails are downloaded into my inbox on my iPad and iPhone. It takes a long time to re delete them. Any advice on how to stop this and, also, why does this happen? Many thanks
You need to ensure your settings are set to also remove deleted emails on your email provider's server so that you will never see them again. Something somewhere is being reset which makes the server think you have not received them before, hence the deluge of old mails.
When setting up a new device for someone I always set the email to only download the last 30 days else they invariably get everything since time began again!