Must all the money stolen from "spam" cards be returned after repentance, knowing that the amounts are large and the perpetrator does not possess the money, and is it permissible to donate some of what was purchased with it?

Stolen money must be returned to its owners. If you do not possess the money now, it remains a debt upon you until you are able to return it. If the theft occurred before puberty, there is no sin upon you, but you are still liable for what you stole. Sincere repentance includes restoring rights to their owners.