Shanghai social security was sealed by the family.

Seizure is the procedure that the employer temporarily suspends the payment of social insurance premiums for employees. If a laborer is detained by a judicial organ, the employer may declare and seal up his laborer in accordance with relevant regulations during the review period after arrest or during the period of disappearance. It needs to be unsealed before it is transferred out.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.