Legal analysis: Generally, when signing a contract, it can only take effect after the final signature. The private seal is also a form recognized by law. If you want to deny that the private seal was stamped, you must provide evidence that the private seal was not used. Otherwise, the contract will be established by default.

Legal basis: Article 490 of the "People's Republic of China and Civil Code", if the parties conclude a contract in the form of a contract, the contract is established when both parties sign, seal or fingerprint. Before signing, sealing or fingerprinting, one party has performed its main obligations and the contract is established when the other party accepts it. Laws and administrative regulations stipulate or the parties agree that a contract should be concluded in written form. If the parties do not use written form but one party has performed its main obligations and the other party accepts it, the contract is established.