Problem with spam in comments

Hello. I have a big problem with spam in comments to DW Q&A question pages. Akismet is activated and block spam questions, but it can’t stop spam in comments. My settings are:
– wp-admin/options-discussion.php – comment must be manually approved + goes to the query when it includes more than 0 links
– wp-admin/edit.php?post_type=dwqa-question&page=dwqa-settings – enable Akismet, Akismet connection status Connected
– wp-admin/edit.php?post_type=dwqa-question&page=dwqa-settings&tab=permission – Anonimous can read and post comments (normal people often post comments on my website pages and I don’t want disable this option for them)
– Commenting possibility is disabled for particular Question page that was attacked by spam today.
– Theme – Envy Blog
Unfortunately this can’t prevent spam comments from automatically appearing on the website. It seems like moderation simply don’t work for them.
Could you please tell me how this problem can be solved?
Thanks