AfterOffice has already filtered off a lot of junk mails at the server level.
You may go to your webmail's [Configuration] → [Statistic] to see the composition of your incoming mail and the percentage of junk mail filtered by our servers.

Email addresses that are published on your website are bound to receive more junk as they are easily pick up by spammers.

There are a few ways that you can consider to decrease the amount of Junk mails received in your inbox:

• Enable junk mail filtering option to filter out high junk rank emails on your webmail. If you have already enabled this option but still get a lot of spams, consider increasing the sensitivity option.
• Black list spam email address so that you will not receive their emails again.

Otherwise, you can request your Administrator to set the Global Junk Filtering option or block the spam email address by using Global Mail Rules.