My sister was selling her house in high-end neighborhood for $127,000 and agent showed for 2 weeks and never again. Got an offer of $80,000 cash and did not accept. Agent refused to aggressively work to sell property. They were forced to sell for the lowball cash offer to local lawyer bcause needed the house sold to move. After deal was made, agent admitted he was partnered with the lawyer in buying the house, hence lack of effort to properly sell house. The partners are flipping the house. This has to be a legal and ethical issue. What can they do? Can they sue the agent? Can they sue the agency? Can they sue for price originally asked for the house? Advice appreciated greatly.