POst by Mail – multiple posts problem – email not deleted

i have configured post by mail.

all is ok and the emails are sucessfully posted using WP Cron.

However, once the cron job has connected to the pop3 mailbox the emails are not being deleted and therefore when i email a post i get loads of posts with the same thing.

it downloads the email, posts it correctly, but because the email is not deleted – the next time ot connects to the mailbox it downloads and posts the same thing again.

any help on this please?

thanks in advance