What is the ruling on one partner taking a portion of the money paid for compulsory insurance in the pension fund without the knowledge of their other partner after the partnership has ended, knowing that this insurance benefits the other partner upon retirement?

It is not permissible to participate in commercial insurance or an insurance fund that contains Sharia violations, if it is by compulsion. However, if a company compels one to do so, then the partners must be fair among themselves in fulfilling their obligations. If one of them evades paying his share, he is oppressing his partners by burdening them with paying his share. And if the money is taken inevitably and the partner refrains, then he has wronged the one from whom the premium due to him is taken. As for recovering the amount paid under compulsion, it is not permissible to take it from the partner's money without his knowledge. The correct approach is for both of you to divide the subscription amount. It is legislated that when you receive the retirement amount, you should take what you both paid and divide it equally, and whatever remains should be returned to the pension authority if possible, otherwise, it should be spent on the welfare of Muslims. If you take the amount from the pension fund, there is no harm in that.