Is it permissible to secure one's right from the company covertly, through a transaction in which delayed financial entitlements are recovered, and to conceal evidence of that, knowing that the company is late in paying salaries and end-of-service benefits?

Increases promised to an employee but not stipulated in the contract fall under the ruling of a promise. The general principle is that fulfilling a promise is commendable unless retracting it causes harm to the promised party. If the increase was merely a promise and did not result in an increase in work or extra effort, then the company is not obligated to fulfill it. However, if it was linked to an increase in the employee's work or an additional cost, then the company is obligated to fulfill it, and the employee has the right to demand it. It is not permissible for an employee to take increases by stratagem unless it is proven that they are his right and the company withheld them from him, and he had no other way to obtain them except by stratagem. It is advisable to refer disputes with the employer to the Sharia judiciary.