Comments submitted despite they are disabled

Lately I’ve noticed that most of the traffic to my site are bots and hackers, and some weird comments started showing up, despite comments being disabled in all posts.
For instance, I just got these comments in the pending queue: https://k60.kn3.net/5/C/9/C/0/1/656.png (the comment text is always part of the text in the actual post).
But when I check the comments area in those posts, it’s disabled: https://k60.kn3.net/6/8/6/D/7/D/EFB.png

How is this possible?
And also related: how can I avoid all these bots trying to hack my site? They waste all of my hosting quota with their visits and failed attempts to log in.
Thanks!