The next step would be to delete the mail account, back up to iTunes on your computer then restore the iPhone through iTunes and set it up from the backup you made after the restore is completed. This will get rid of all that data being used by your mail account.I have tried everything, including taking phone to Verizon store for help. Deleted all messages in all boxes in all mail accounts; deleted all mail accounts. Any way to access and delete mail memory? Or?