Is the salary considered usurious, and is it obligatory to leave the job if a portion of it is based on a percentage of late payment penalties imposed on customers, taking into account the difficult economic circumstances and the lack of other job opportunities?

We have previously clarified the permissibility of working in entities whose primary activity is lawful, provided that the employee does not directly engage in what is forbidden, nor directly assist in it. If the work is permissible, then the salary is permissible.

We also explained that stipulating a fine for late installment payments is forbidden interest (riba).

If you are directly involved in this usurious condition regarding the late payment fine, and you have not found work free from this prohibition, and you are compelled to it because you cannot find what to spend on yourself and those you support, then there is no blame upon you; because necessities permit the prohibited, along with the obligation to diligently search for a way to exit this necessity.