Fake amazon.com emails

[NilesF]

Hello,

We have a customer on our filter that seems to be receiving a ton of amazon.com fake emails. These emails seems to slip right through the filter which is running:

razor
pyzor
dcc
spamassasin
postfix

postfix is configured to use spamhaus, spamcop and dnsbl.org

Wondering if anyone has experienced this and what can be done to rectify?

thanks

NF