My chatroom says it has reached it's limit and to open vip shop why has other player not heard of this?

The game generally has 1 main chat (Province) and a second for the Alliance if you are in one. During RoC Eden events there is also a Guild chat thread.

This is it for most players. For VIP players one of the benefits you can unlock is a private chat thread that you can invite people to. Most people don't bother with this though and use external chat apps to make groups for their friends or specific players.