All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
What this company is doing is nothing but forbidden cheating, unlawful forgery and consuming people’s money without right, so it must stop doing so.
Therefore, if the work of the company is based on this cheating, then it is not permissible for you to work for it as an accountant or in any other job as this is helping them in sin and transgression because Allaah forbade cooperating in sin and transgressions as He Says (what means): {Help you one another in virtue, righteousness and piety but do not help one another in sin and transgression. And fear Allaah. Verily, Allaah is Severe in punishment.}[Quran 5:2]
Since working for this company is forbidden, then the salary taken from it is ill-gotten money. Therefore, you are obliged to abandon working for this company unless its owners stop cheating, forgery and consuming people’s money without right.
As regards the items and the like that you purchased with the salary, or the money that you still have from previous salaries, then it is permissible for you to benefit from it as you did not know the ruling on that job; so you are excused as Allaah Says (what means): {So whoever has received an admonition from his Lord and desists may have what is past, and his affair rests with Allaah.}[Quran 2:275]
Allaah Knows best.