Can't delete an old email message on my iPhone, it also shows 2 new emails that aren't present

My iPhone shows 2 new email messages in my inbox but there are none. It also has an email from January of 2012 that I can't delete. I think it may be somehow related to sync'ing with my Exchange account but don't know how to resolve. Anyone else have these problems and discover how to resolve them?

Many thanks,

-Paul.