Should the employment agency's commission be paid based on the salary agreed upon in the old contract, or on the higher salary after renegotiation, keeping in mind that the agency is unaware of the new salary?

The commission stipulated by the recruitment office must be paid if agreed upon, whether it is a known amount or an unknown amount whose ignorance does not prevent delivery, such as the first month's salary. The calculated commission is based on the actual salary received by the employee, whether it increased or decreased from what was mentioned in the initial contract.