In the event of a match starting but not being completed, the player progressing to the next round will be deemed the winner (or in the final, the player declared the winner).
For Correct Score, Next Frame, and Handicap markets, if a match is not completed for any reason, bets will be void unless the market has been unconditionally determined.
The Exchange General Rules and Market Information will apply in respect of any category of bets or markets not referred to in the Specific Sports Rules. If there is any inconsistency between the Specific Sports Rules and the Exchange General Rules, the Specific Sports Rules shall prevail. If there is any inconsistency between the Market Information and either the Exchange General Rules or the Specific Sports Rules, the Market Information shall prevail.
See here for the Exchange General Rules.