Sellers cannot start a chat with buyers on your marketplace unless there has been a successful transaction between the buyer and seller or the buyer initiated the chat first.
For sellers to start a chat with buyers who have already made a successful transaction for a product/service, they can contact the buyer by finding the successful order on their order list and clicking the “Message” button.
For sellers who want to contact buyers who have previously contacted them before, they can click on the chat inbox button at the top bar to find the previous chats.