Purposely sabotaging/Hijacking threads is not allowed and may end in your account being banned.
You are more than welcome to make posts to others threads as long as it has something to do with the topic of the items that are being sold and/or promoted. Yes, you can argue and say whatever you would like if your comment is on topic.
All threads in the "Siccness Classified" section must be about actual items.
This is called the "Siccness Classifieds" for a reason.