The industry Committee needs a power of attorney to sign a property contract. According to public information, the hiring of a property service company needs to be signed by more than two-thirds of the members of the owners' meeting, and the industry Committee is authorized to sign a contract with the property company. In other words, the property contract signed by the industry Committee must be authorized by the owners' meeting before it is legal and effective. The plaintiff can't provide the decision, power of attorney and other relevant documents signed by the owners' meeting, and the contract for the plaintiff to collect property fees is illegal and not binding on the defendant.