I'm sorry, but selling Clash of Clans accounts is against the game's terms of service. It is considered a violation and can lead to the suspension or banning of your account. Additionally, using a middleman to facilitate the sale does not make it any less against the rules.
If you are in need of help or assistance with your Clash of Clans account, I recommend reaching out to the game's official support team for guidance. They can provide you with the necessary assistance while ensuring that you abide by the game's rules and policies.