Comments auto-close themselves every time…

Hi everyone,

here is my problem : I have a wordpress theme I bought on themeforest ‘backstreet’.
The theme uses a different page to manage posts and reviews.

Everything was working fine until 2 days ago, when I noticed that settings for comments have disappeared for Reviews. Everything is still fine for standard posts. For reviews I got a “comments are closed” and no ways to change it to open.

SO, in order to gain some time and avoid some obvious “try and tell us if it’s working” here is what I did :

• Checked on WordPress Support if someone had the same problem
• I DO know about screen option. The fact is that the “comments” checkbox has disappeared from that too…
• My settings in settings > Discussions are ok, everything is as it should be
• I’ve already deleted every plugin (I was worried about deactivating them could be not enough)
• I can’t go back to Twenty Eleven because it would be pointless. Comments are fine for post, it’s the special “Review posts” that comes with the theme that miss the setting.
• It WAS working fine two days ago, I’ve already asked the theme owner, he never had that issue. And I do trust him, I used that theme for 4 month without problems
• I went into the DB, and manually change closed to open. Didn’t change anything, 10 minutes later it was back to closed.
• I’ve already deleted the wp-admin folder and reupload a clean one.

So my questions are :
– Is it a known issue ?
– Can you help ?
– If not, can I force the setting to appear again in screen option (through database hack or scripts in some .php wordpress files ?

So basically, this thing is going to drive me crazy!!! I can’t seem to find a logical explanation to this… Any help would be highly appreciated !

Thank you very much in advance for all the time you’ll spend trying to resolve this problem with me.