Can't you quit your job if you haven't bought social security for one year?

There is no such thing, resigning or not resigning has nothing to do with the length of participation;

On the other hand, according to the Labor Contract Law, an individual can leave a job after one month of submitting a resignation. If the employer forces the worker to work by violence, threat or unlawful restriction of personal freedom, or if the employer endangers the worker's personal safety by directing or ordering risky work against the rules, the worker can terminate the labor contract immediately without informing the employer in advance.

Good luck