What is the ruling on paying a lump sum or installments to purchase additional years in social security to increase the retirement pension?

This type of social security involves usury (riba), uncertainty (gharar), and harm (darar). The state collects installments from employees and invests them in interest-bearing loans, then pays out the profits. If participation is optional, do not register your name. However, if it is compulsory and there is a necessity, then benefit only from the amount that was deducted from you, and give the rest in charity.