Serve (someone) right

Serve (someone) right: (alguém) merece algo pelo que fez, o que está acontecendo é consequência de algo ruim que esse alguém fez ( portanto merece)

“You knew it was illegal to smuggle drugs, and now you're in jail. All I can say is it serves you right.”

“They're so lazy that it'd serve them right if they failed their exams.” (www.englishclub.com)