What punishment befalls devils who break their contracts?

In Mordenkainen’s Tome of Foes (p. 10), it is stated that Asmodeus’ Ruby Rod binds all devils to the letter of the law of their contracts. Failure of a devil to keep their end of the bargain in a contract would subject them to an inescapable punishment, but the nature of the punishment is not elaborated upon. I assume it’d be something ironic and debilitating.

The [Ruby Rod]…grants him and his underlings the right to enter into contracts with mortals for their souls but unleashes an inescapable punishment upon any devil that breaches such a contract.

Is there any official clarification on the nature of the punishment? If an answer is not available in 5e, I will accept an answer from other editions.