What is the reason why social security can't be bought?

Social security can not buy into what is the reason , the following with me to briefly understand it.

1, the user's previous employment company is still paying for the individual in the social security, resulting in the current employment company can not pay the social security;

2, the individual is now employed in the company's personnel department or human resources management department of the operation of the work of dereliction of duty, resulting in the inability to pay the social security;

3, some companies use the social security as a front to carry out fraudulent behavior, cheating money.

These are the three reasons why social security may not exist.

Expanded knowledge:How to pay social security to employees?

To open a social security account, the unit needs to go to the Social Security Administration for social security account opening within thirty days of the date of establishment, social security account opening will receive the "social security registration certificate".