You are fully allowed to give ur opinion (as long as you follow the rules). PM the mod of that forum and talk to him/her. He/she shud explain you why the thread was deleted. If you still cannot resolve the issue, THEN you can open the thread here in feedback :)
You have a total of 9 posts as of today and I just searched for all of your posts, I was able to see all of them in forums. None were deleted as far as I can see. You can view them yourself by clicking on your name.