Assalam aley kum

I have spent the sadqa money on self. So please can you answer me what will be the way of returning the amount or kaffara for the amount. I am very disappointed for many of the peoples who have denoted

That is up to your elders to determine how this money will be repaid. Or the ones who have donated. That means you start with informing your elders of your transgression and submit to their will.