Praise be to Allah.
Selling visas is not permissible, because it involves telling lies, breaking the law and deceiving the authorities, and it is consumption of wealth by means of falsehood. Allaah says (interpretation of the meaning):
“And eat up not one another’s property unjustly (in any illegal way, e.g. stealing, robbing, deceiving), nor give bribery to the rulers…” [al-Baqarah 2:188].
On this basis, the money you earned from selling the visas and the money you took from the workers is haraam income, so you have to get rid of it and clear yourself of it. Whatever you have obtained by selling visas, spend it in charitable ways such as giving to the poor and building facilities that will benefit the Muslims.
Concerning the money which you have taken from the workers themselves each month, you have to give it back to them if they are still in the country, or try to send it to them in their own country. If you could not find out where they are or send it to them, then give it in charity on their behalf, because this money was deducted from them unlawfully and they were not compensated for it. You have to keep on repenting for this action, and never repeat it in the future. Whoever gives up something for the sake of Allaah, Allaah will compensate him with something better. Allaah says (interpretation of the meaning):
“And whosoever fears Allaah and keeps his duty to Him, He will make a way for him to get out (from every difficulty). And He will provide him from (sources) he never could imagine” [al-Talaaq 65:2-3]