If you have too much SPAM passing (even if you are forwarding the errors to assp-spam@yourdomain.com), you can increase the sensibility of your antispam raising it from normal to high, higher or highest in your ASSP section in your cPanel. If the SPAM is passing also with high, higher or highest settings, please check the email headers, most probably the sender is whitelisted.
You can then remove the sender address from the whitelist sending an email to assp-notwhite@yourdomain.com with the sender email address in the body of the message.
