What is the ruling on recording and listening to incoming calls to the company, whether or not the employee and the customer are aware of it, and what is the ruling on selling this program without obliging the customer to add an audio notification stating that the call may be recorded?

Eavesdropping on others' private calls and recording them without their permission is forbidden, unless it is highly probable that a crime has occurred which cannot be prevented except by this means. Jurists have excepted from this prohibition cases of necessity in which spying is permissible, such as saving a life from destruction. As for designing a program to record calls, there is no harm in it if it is for achieving a public interest, provided that both parties to the call are informed of the recording. The possibility of misusing the program does not prevent the permissibility of designing and selling it.