Verified answer

Yahoo is still having some problems at the moment. If you look you will find lots of people cannot send/receive/delete mail at the moment. I was advised to uninstall Javascript and then reinstall the latest version. This worked for me. If it does not for you then apparently it's only in the all new version. Try returning to the Classic version for now. I am also told that the mail is in fact there in your box and is being sent. It's simply invisible in all new mail. Good luck use this link to get back http://us.mg1.mail.yahoo.com/dc/optout?script=no