When I have an issue that I can't resolve I do the full restore through my iTunes on my home PC. This has always worked for me as a last resort. That was mostly on my iPhone 3G. Haven't had to do it since switching to the iPhone4
All has gone well for some time. Suddenly stopped downloading my mail as of last Thursday. I have closed all programs and restarted the Iphone as I had to do once before. No luck. Any suggestions??...
Catkins, I have a suggestion for you that came up for me in the past. Does your email/internet service provider have a maximum space allowance on your email account? I ask this because by default the iPhone is set to leave a copy of the email on the mail server. If you haven't cleared that out via your home computer your email account may simply be in a holding state waiting for you to do this. If you have someone trustworthy who you can send your email password to at home, ask them to fire up your computer at home and check your email. Odds are that it will spool for quite awhile if you have been on the move for awhile. I suggest this as I ran into this issue with my primary service provider account no longer delivering me new emails that I knew were being sent to me while I was out of the country for awhile.
To keep your email account thinned out you can change these settings on your iPhone by selecting the "Settings" icon from your springboard and scrolling to "Mail, Contacts, Calendars." From there select the email account in question and scroll down to the "Advanced" tab and look in the "Incoming Settings" field. In that field will be a line that allows you to adjust these settings to match your preferences. Personally, I select "When removed from inbox" because if it's important enough to keep at home I can keep it on the iPhone until I download it at home.
Hopefully you've already sorted this out and if you haven't this will help. have fun out there and keep us posted.
Do you sync your iPhone on a computer? As a last resort, you can sync the device, backing up everything (apps, music, photos, etc.), do a complete erase, then DFU restore the iPhone (YouTube has videos on how to do this right), which will re-flash the device, then you can reload all your stuff on it.