The company must pay social security for its employees, which is a legal obligation. Even if the workers themselves are unwilling to pay the company, they should also pay social security for them.
According to Article 58 of the Social Insurance Law:
The employing unit shall, within 30 days from the date of employment, apply to the social insurance agency for social insurance registration for its employees. If the social insurance has not been registered, the social insurance agency shall verify the social insurance premium it should pay.
Article 38 of the Labor Contract Law stipulates that if the employer fails to pay social insurance premiums for the workers according to law, the workers may terminate the labor contract, and the employer shall also pay economic compensation.