We have very extensive spam filters which in the main are very efficient and react rapidly to new threats as they are created by the spammers.
Unfortunately spam is something that is very difficult to totally prevent.
There are three simple things that can be done to reduce the spam further once it hits your Outlook email client.
1. right click on it and block sender.
2. right click on it and select RULES and send all mail with specific subject or key words to your junk email
3. log onto your spam filter (mail.miit.co.nz) navigate to your anti spam management and black list sender, domains or IP addresses for your specific email account.
In any one month the SPAM filter blocks in excess of 12,000 spam emails per mail box and when the spam filter software has to catch up with new spamming technics 5 - 10 spam emails per day, although annoying, is on the low end of the scale. We can raise the spam filter level higher how ever we then run the serious risk of blocking legitimate emails.
I hope this helps to some extent even although it is not a 100% solution.