What are the reasons for the contradiction between Xie Guangkun and Liu Neng?

Meng Xiao can't get pregnant. When Liu Neng went to the market, he met an acquaintance's son, who sold ancestral secret recipes to treat infertility. Liu Neng spent 10 dollars to buy a prescription for Xie Guangkun. He told Bigfoot and Wang Yun at the gate of Bigfoot Supermarket. Xie Guangkun felt insulted when he heard this. He quarreled and left. He passed Liu Neng's house and threw a bottle into his yard. It happened that Liu Neng's granddaughter was playing alone in the yard, chasing the dog. Liu Neng's wife saw Xie Guangkun's back after throwing the bottle and thought that Xie Guangkun had taken the child away. After that, Meng Xiao saw the children on the roadside on his way home and took them home. They have been quarrelling ever since. . .