How can the amount of ill-gotten money, saved from a work trust without the employer's knowledge, be determined, and what should be done about it if this action would lead to losing the job?

The third portion of the saved money (the trust) may only be spent to the extent needed for the work. Any excess must be returned to its owner. If you do not know its exact amount, you must pay from your own money an amount that you predominantly believe equals it, and it is preferable to add more as a precaution and to clear your conscience. Return the money by an appropriate means without informing the employer of what actually happened, such as sending it via a transfer in the company's name, noting that you previously took this money, without mentioning your name.