If you're ever in the position where your agent attempts to sell your house to an un-mortgageable buyer and no one notices until after you have exchanged contracts (on both sides of your chain), you're then involved in months worth of legal issues, King Group WILL try to charge you their commission.. Change your contract wording to state commission becomes payable upon completion, not on exchange of contracts. Even though my contract was amended to state 'no sale, no fee' they are still perusing their fee. I have now had to instruct a solicitor to try and uphold our contract. Formal complaints have been submitted, complaints will also be submitted to The Property Ombudsman and the National Association of Estate Agents.