You choose not to return it.  You can't get a second job, set aside some % of your paycheck, return the item you bought, sell possessions, sell the item you bought with stolen funds, offer to mine at 100% donation, etc?  Really?

You really expect people to believe it PHYSICALLY impossible for you to return the funds you stole in any other manner than a 20% donation on future mining. 

You stole money and choose not to repay it.  There is no CAN NOT.   You are choosing to remain a thief, liar, and piece of shit!  Lets stop pretending ok. Obviously nobody can force you to return the funds but be a man and be honest (at least to yourself) about your complete lack of morals.