Hi Diamondcyborg
The rules state clearly you are not allowed to advertise in chat. When you have something for sale, buy a mall plot and create a chest-shop for it.
When you are looking for something, you can ask people in chat if someone is selling. They can reply to your question, but not start advertising it to others.
If you feel like you do not understand the rules or do not agree with them, you can take it up with someone from staff (Moderators or Headmods) and they will provide you with a suitable answer and clear out the issue.
kind regards
-Skelly-