How can a consumer's refusal be recorded?

Question

Algorithms

There is an organization that provides a payment service for consumers. Consumer payment is fixed through the application on the phone. The consumer pays the amount, and the manager drives it into the database. The consumer also has the right to refuse the service.
Situation: The consumer pays a certain amount, but the manager does not enter this into the database and takes the money into his pocket.
Question: How can the consumer's refusal of the service be recorded in order to avoid theft by the manager?
We thought about the option with a camera like the promoters, but the number of managers is more than 250 people, the working day is 7 hours. That is, viewing 1750 hours at the end of each working day is not an option.
Any thoughts?

Answer 1

In case of refusal, send the customer a 3-digit confirmation code so that it is not available to the manager. Check for the presence of the code in situations where there is no payment.

Answer 2

1. View records selectively. Do this more often for those managers about whom there are suspicions. Regularly inform managers that the record is being made. If there are violations - to arrange a demonstrative flogging, so that it would be disrespectful. If there are no violations, find any little things and arrange their public analysis.
If managers keep in mind that big brother is watching them, that might be enough.
2. I didn’t quite understand something from the description - how the payment is made, that the manager can pick it up for himself. Can you explain?