What is the expiation for taking a portion of donations designated for aiding the families of detainees? Are good deeds and supplications accepted before repaying this amount? How can one get rid of the love of money and desires? And what is the punishment for this act?

It is obligatory to repent to Allah Almighty for betraying trusts and unlawfully taking money. This is done by ceasing the sin, regretting it, and resolving not to return to it, and by immediately returning the right to its rightful owners if possible, or otherwise according to one's ability. A sound repentance makes acts of worship accepted, and one is not punished for the sin thereafter. As for overcoming desires, it is achieved by purifying the heart, turning to Allah through self-struggle, frequently remembering death and the Hereafter, and increasing in remembrance [dhikr] and supplication [du'a].