Incomplete question. However, I assumed you are referring to the story, "Holes " by Louis Sachar.
Explanation:
We find the reason why Elya failed to keep his promise to Madame Zeroni in chapter 7 of the story. When the day arrived that he brought the pigs to Myra's house he then discovers that Myra has no concern about who she marries, he felt disappointed and immediately decides to get on a boat heading to America, which made him forget his promise to Madame Zeroni.
