[Exim] Exim Catchall Problem

Hi all,

I am having a problem with exim delivering local mail, every domain on the
server should receive anything @theirdomain.com, but if an accont does not
exist on that domain, instead of going to that users default mailbox it is
stored in the root email account on the server, I have checked all the
valiases files and they all seem to have '*: username'

Any ideas would be very appreciated, Thanks