The antonyms for the phrase "call bets off" would be "follow through," "carry out," or "complete." When someone calls bets off, they are cancelling or declining to go through with a planned activity or event. Instead, following through would involve seeing something through to completion, regardless of any obstacles or changes in circumstances. Carrying out encompasses the idea of completing a task or responsibility from start to finish, without dropping the ball. Completing something involves not only finishing but doing so in a thorough and satisfactory manner. These antonyms suggest a sense of commitment and dedication that is absent in the act of "calling bets off.