There are many factors leading to the ads being shown on the first page.
Usually lbc shows the ones who are online right that moment with priority from the most trusted ones. Also it appears they have an algorithm which matches the history of the user to throw suggestions.
Sometime may be technical issue in the site but you should have some certain amount as escrow fund your wallet. If you are not fine with the escrow amount in your LBC site you need to add it accordingly or you need to send the email to support team to sort out your issue.