What should a person do with money given to them to subvert a legal ruling, which its owner refused to take back after the person repented?

There is no harm for your companions in benefiting from the money you offered to its owner, who refused to accept it and absolved you of it willingly. This is because the original transaction by which the money was acquired does not affect the permissibility of the money for you after your repentance and its return, as long as its owner has gifted it to you.