People's Republic of China (PRC) Civil Code
Article nine hundred and twenty-eight
If the agent completes the entrusted affairs, the principal shall pay the remuneration as agreed. Now that the cost consultation unit has completed the whole process of cost consultation, the construction unit should pay the remuneration to the cost consultation unit according to the agreement, and the main body of remuneration should be the construction unit. Article 523
If the parties agree that the third party shall perform the debt to the creditor, and the third party fails to perform the debt or the performance of the debt does not conform to the agreement, the debtor shall be liable to the creditor for breach of contract. Therefore, if the construction unit fails to fulfill its payment obligations, the construction unit can only bear the liability for breach of contract to the cost consulting unit.