Be there or be square! (Won't leave until we meet!)
Tips
usage
不见了 is the standard way to say something has gone missing or disappeared. 好久不见 is one of the most common greetings in Chinese — it's actually the origin of the English phrase 'long time no see.'
culture
不见不散 (bù jiàn bù sàn, lit. 'won't leave without meeting') is a popular way to confirm plans — meaning 'I'll wait for you no matter what.' It's also the title of a famous 1998 Chinese romantic comedy film.