All perfect praise be to Allah, The Lord of the Worlds. I testify that none is worthy of worship except Allah and that Muhammad is His slave and messenger.
Muslim scholars are of four opinions concerning the matter of dealing with a person whose money is mixed with what is unlawful.
1. Dealing with such a person is forbidden.
2. It is permissible.
3. If what is unlawful dominates his earnings then dealing with him is forbidden otherwise it is dislikeable.
4. It is dislikeable only.
Some contemporary scholars give preference to the ruling that dealing with such a person is dislikeable only.
We conclude that as long as the majority of the income of this company is from lawful sources, then your work there is not forbidden but it is not desirable.
Therefore, we advise you to try to get rid of this job in the nearest future since one should take precautions not to deal with doubtful matters.
An-Nu’maan Ibn Bashir said: “I heard the Prophet saying: “That which is lawful is clear and that which is unlawful is clear, and between the two of them are doubtful matters about which many people do not know. Thus he who avoids doubtful matters clears himself in regard to his religion and his honor, but he who falls into doubtful matters (eventually) falls into that which is unlawful, like the shepherd who pastures around a sanctuary, all but grazing therein. Truly, every king has a sanctuary, and truly the sanctuary of Allaah is His prohibitions. Truly in the body there is a morsel of flesh, which, if it is sound, all the body is sound, and if it is diseased, all the body is diseased. Truly, it is the heart.” [Al-Bukhari and Muslim]
For more benefit on dealing in doubtful matters, please refer to Fataawa 321307, 85295, and 332797.
Allah knows best.