Why did the shopkeepers refuse to give Baba oil, and how did they react after he performed the water-to-light miracle?

According to Chapter 5, Sai Baba would bring oil for free every day from the local grocers to light lamps. After some time, the grocers developed a 'wicked idea' and conspired together to stop what they considered a 'nuisance.' When Baba came to ask for oil as usual, they all refused him. However, after they witnessed him miraculously light the lamps with water, which then burned all night, they were amazed. The text states they felt deep repentance, realizing they had sinned by lying and giving Baba needless trouble. They put their fingers in their mouths in astonishment and began to tremble.