I have a host and am constantly receiving emails being returning that I have sent to email addresses at AOL and Yahoo. The problem is I am using a shared server and would assume that other users are either sending out huge amounts or mail or sending spam and I suffer because my emails are not being received. My host does eventually get back on track however it happens very often.
I have Outlook 2007 - Windows 7
Is there any way that I can circumvent this from happening?

As far as I can see the only way is to change your host or move your mail server in-house.