Praise be to Allah.Praise be to Allaah.
What seems to be the case is that it is permissible to work in this company so long as the work that you are doing is halaal. With regard to working in companies whose work is permissible, the ruling is different with regard to working in banks and other riba-based institutions. In the bank, the employee is sinning whether he is working as a clerk or witness or even as a guard, because the work is haraam in the first place, unlike if the bank has a share in part of the capital of a company whose work is permissible. In this case it depends on the nature of the company's work; for example, it is permissible to work with Jews, Christians and those who deal with riba, although it is makrooh.
Ibn Qudaamah al-Maqdisi (may Allah have mercy on him) said:
Ahmad said: A Muslim may enter into a partnership with a Jew or a Christian, but he should not let the Jew or the Christian be in charge of the financial affairs to the exclusion of the Muslim, because they may engage in riba. This is the view of al-Hasan and al-Thawri.
Al-Shaafa’i regarded such partnerships as makrooh in all cases. End quote.
Ibn al-Qayyim (may Allah have mercy on him) said:
Iyaas ibn Mu‘awiyah said: If a Muslim goes into business with a Jew or a Christian, and the money is with the Muslim and he is the one who will do the buying and selling, there is nothing wrong with it, but he should not give it to the Jew or Christian to deal with it, because they deal with riba. End quote.
Ahkaam Ahl al-Dhimmah, 1/93
You will find more details on this issue in the answer to question number 48005, at the beginning of which we said:
If a person earns money in haraam ways such as riba, bribes, stealing and cheating, etc., and his wealth is a combination of halaal and haraam, then it is valid to do business with him, buying and selling and entering into partnerships, but it is makrooh. If it is known that the product in which the trade is to be done is haraam in and of itself, then it is not permissible to enter into a partnership with him or work with him in that business..
Based on that, the money that you are taking from this company (the salary) is halaal, in sha Allah, and there is nothing wrong with what you have spent or saved.
And Allah knows best.