He took some money from the company that he was not entitled to, and he cannot tell them about it
Question

                The company where I work gives land as grant and it gives also interest free loans, So that the employee can have a house. The company gives two options for this; whether to wait until the company finds land for you or to find land yourself that does not cost more than 150.000 SR. then the company gives the employee the cost of the land as written in the contract. If the land costs for example 100.000, the company gives only this amount. A brother said to me there is no problem in buying a land and writing it for 150.000 in the contract even if it is cheaper than this; so that I take the maximum grant from the company.   

I bought a land for 75.000 SR and registered it for 150.000, and the company gave me 150.000. I started afterwards building a home on this land after I received some payments. Now the home is nearly built.  

I discussed this matter with a brother who told me that what I did is cheating. I feared and doubted what I did. If I knew that what I have done is haram I would not have done it. I would have also bought a more expensive land which would be better in terms of position and size than the land I bought.  

I need this money as I have a debt of 400.000 SR to pay off.  Please tell me the ruling on this. Do I have to return this money to the company, knowing that this may harm me, and they may fire me.
Praise be to Allah.
    If the company gives land to its employees that does not cost 
    more than 150,000 riyals, and it gives them the amount that is recorded in 
    the sale document, then it is not permissible to record more than the real 
    price, because that is lying and consuming wealth unlawfully, and because 
    the Muslims are bound by their conditions, and the contract between the 
    company and the employee states that they will give him the price of the 
    land to build a house, not to save it. 

    Based on that, you have to repent to Allaah, may He be 
    exalted, and return the extra money to the company. If you think it most 
    likely that unbearable harm will result if you tell the company about this 
    matter, then look for means of returning the money to them without them 
    knowing. 

    Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said: If 
    you steal from a person or an organization, then you must get in touch with 
    the one from whom you stole and tell him, “I have such and such of yours,” 
    then you should work it out between you. But some people may think that this 
    is too difficult and that they cannot go – for example – to someone and say 
    “I stole such and such from you” and “I took such and such from you”. In 
    that case he can send this money – for example – to him by some other means, 
    indirectly, such as giving it to someone who is a friend of his and also of 
    the other person, and telling him, “This is for So and so”; he can tell him 
    the story and say, “Now I have repented to Allaah and I hope that you will 
    give it to him.” 

    If he does that, then 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)”

    [al-Talaaq 65:2] 

    “and whosoever fears Allaah and keeps his duty to Him, He 
    will make his matter easy for him”

    [al-Talaaq 65:4]. End quote. 

    Fataawa Islamiyyah (4/162). 

    We ask Allaah to make things easy for you, and to help you to 
    pay off your debt. 

    And Allaah knows best.