When a crime has been committed, it is quite common for the perpetrator to be ordered to pay the victims of the crime an amount of money. This is different than a fine, because the purpose of a fine is to punish the perpetrator. An order of restitution has a practical side to it; it helps the victims of the crime financially.
Fraudulent activity in relation to creating Ponzi schemes is considered a relatively common white collar crime. It is a type of investment fraud, since the organizers earn money through scamming new members of the scheme.