Ok, this is a fairly new annoyance to me. It started a couple of weeks ago on my iPhone 3G and has continued on my iPhone 4. Basically, I have the settings for my Hotmail account set to fetching new data hourly and notifying me via Push. However, whenever I get some new emails and then delete them, it then sends through the next most recent 50 emails, when I delete them, it sends the next most recent 50 emails and so on and so on. It will just keep sending me older and older emails as though every email in that Hotmail account is a new one. I'm sure deleting every single email in my Hotmail account will solve this but I have a lot of emails I don't want to delete incase they need to be used for reference at a later date. There is that many emails in my account though that I can't possibly find every one of them unless I do a search. Is there anyway to stop my iPhone from sending me emails any older than say, today?
The mail is seriously... uncustomizable is the word I'm looking for, but there's a red squiggly like under it, so maybe not? Anyways, I've been looking for a multiple delete option (select 20 or so messages, then delete them all at once) and scoured far and wide for some sort of workaround. I haven't found an option or switch to toggle for what you mentioned. The app doesn't hold a match to even a web client.
It does that every once in a while on my business email (from my website). Whenever they update anything, all of my old mail turns into new mail according to my iPhone. I've found no way around it. I just tap edit and delete everything.