Legal analysis: the contract signed by the buyer's intermediary is generally legal. A civil juristic act that violates the mandatory provisions of laws and administrative regulations is invalid. However, unless mandatory provisions do not invalidate civil legal acts. A civil legal act that violates public order and good customs is invalid.

Legal basis: Article 153 of the Civil Code of People's Republic of China (PRC) is invalid if it violates the mandatory provisions of laws and administrative regulations. However, unless mandatory provisions do not invalidate civil legal acts. A civil legal act that violates public order and good customs is invalid.

Article 961 An intermediary contract is a contract in which the intermediary reports to the client the opportunity to conclude a contract or provides media services for concluding a contract, and the client pays the remuneration.

Article 502 A lawfully formed contract shall become effective upon its formation, unless otherwise provided by law or agreed by the parties. In accordance with the provisions of laws and administrative regulations, if the contract should go through the approval procedures, such provisions shall prevail. If the failure to go through the formalities such as approval affects the effectiveness of the contract, it will not affect the performance of the obligation clauses such as approval and the effectiveness of relevant clauses in the contract. If the party that should go through the formalities for approval fails to perform its obligations, the other party may require it to bear the responsibility for violating its obligations.