She swore that she would not eat from their wealth unless they stopped dealing with bonds concerning which the scholars differed
Question

                I live in a gulf country. People here started dealing with what is called (national cheques) and are saying that it is halal. So I started using them as well as my family did. Some time after this some scholars (including the mufti of one of the emirates) said it includes Islamic restriction and they informed the Islamic bank about them but the bank did not fully investigate.

So now these cheques are disagreed upon some say it is halal while others say it is haram. When I knew this I told my family that I want to withdraw from such transactions and I have already withdrawn Alhamdulillah. I advised my family to withdraw theirs but they did not respond to me. I swore that I would not even drink a cup of water if they win any extra amount and I repeated my oath in different occasions, not at the same time. What shall I do? How shall I expiate? Is it permissible for me to eat from what is made of this money? I really do not want to even drink water which is bought by this money, what shall I do? Please answer me. I am a girl and I cannot live alone.
Praise be to Allah.Firstly: 
The one who wants to engage 
    in some transaction with a company or anyone else must know the rulings on 
    that, and find out whether it is Islamically acceptable, either by 
    researching it himself or asking the scholars, as Allaah says 
    (interpretation of the meaning): “So ask of those who know the Scripture, 
    if you know not” [al-Nahl 16:43].   
If you subscribed to these 
    bonds following a fatwa issued by a trustworthy scholar which said that they 
    are permissible, then there is no sin on you. 
If a person is sure that 
    they are haraam, then it is not permissible for him to subscribe to them. If 
    a person subscribes to them then finds out that they are haraam, then he 
    must get out of it, and there is no sin on him for what happened in the 
    past. 
You have done well to get 
    out of it and withdraw your money. This is safer and better. 
Secondly: 
If your family do not think 
    that they are haraam, then they do not have to get rid of these bonds, 
    because they followed the fatwa of one who said they are permissible. If 
    they are not qualified to know the difference and determine what is more 
    correct, and they rely on following a scholar whom they trust, there is no 
    blame on them. 
Thirdly: 
It is permissible for you 
    to eat and drink food and drink offered to you by your family, because their 
    wealth is mixed, and because wealth that is haraam because of the manner in 
    which it is acquired is haraam only for the one who acquires it and not 
    others who take it from him by permissible means. See the answer to question 
    no. 45018. 
With regard to your oath, 
    if you wish you may adhere to it, and not benefit from anything that results 
    from the profits of these bonds, whilst benefiting from their other wealth, 
    or if you wish you may offer expiation for breaking your oath. 
You only have to offer 
    expiation once, because the one who swears repeated oaths concerning the 
    same thing only has to offer expiation once in the event of breaking the 
    oath. See the answer to question no. 
    38602. 
And Allaah knows best.