1. Where do the topics go? after a Minute I set my eyes on it and I come back again to check for that topic I won't find it

Off-topic replies have become a big problem. From now on, I will be deleting such replies without notice, forum-wide. If your replies disappear, this is probably why.

2. Who has access to locked topics in the forum apart from the creator of that topic?

"Moderators" moderate specific sections. They can delete posts there, edit them, move topics, split topics, lock topics, and sticky topics. "Global moderators" are the same as moderators, but they moderate all sections. All staff can also whitelist newbies and ban newbies. Administrators can do anything.

Any user can report a post. The report is send to the admins, global moderators, and any applicable section moderators. The recipients choose to act on the report or not.