missing comments section

Hello,
ia m very new to wordpress. I have just created my first blog. I am using the mantra theme. My problem is that my comments section is not appearing after my posts. I am sure i have it configured correctly in the post information settings and discussion settings panel. I found a thread about a short bug on the mantra website. (here is a link to that post:https://www.riotreactions.eu//?s=short+bug) I edited the code as they said and uploaded the fix only file via ftp. It seemed to work at first, but now my comments have disappeared again! Also, now when i have scrolling posts, the comments don’t show up, so i dont think its a short bug issue.
when i switch to a different theme, comments show up there. Please help! This is making me crazy!