got a google hacked alert on a client site that is running defender

Hi,
I got a google hacked alert on a site that is running defender. I have support access on. Can you tell me how to best handle the issue it found? all plugins are up to date and the site is hardened.

Alert - Hacked content found on http://www.bizrainmakers.com/

To owner of http://www.bizrainmakers.com/,

Google has detected that some of your webpages have been hacked by a third party who may have created spammy or malicious content on your site. This lowers the quality of results for Google Search users and affects the reputation of your site. We have applied a manual action to your site that will warn users of hacked content when your site appears in search results. It will protect our users from malicious content present on the site. To remove this warning, clean up the hacked content and file a reconsideration request. To protect yourself from this happening again, we also recommend you secure your site against intrusion by implementing industry best practices.

Following are some example URLs where we found pages that have been compromised. Review them to gain a better sense of where this hacked content appears. The list is not exhaustive.

http://www.bizrainmakers.com/charcandrick-west-jersey-or-alternatively-individuals-wear-so-that/

http://www.bizrainmakers.com/dan-bailey-jersey-consisting-of-28-marks-in-paradigm-leagues/

http://www.bizrainmakers.com/leveon-bell-jersey-cheap-then-definitely-do-an-admirable-job/