It should be handled by civil law. The leagues sell tickets to fair competition. If the players fix the match, then the league is selling a defective product, and common sense suggests they should refund the ticket sales. And the players were presumably contracted to provide fair play, so if they damage the league by breech of contract then common sense suggests the league should be able to sue the players responsible for the cost of the refund. They could require players to take out insurance to ensure they'll always be able to pay.

Making it a criminal matter is just a subsidy to the gambling industry.