The company failed to pay social security, so I asked the company to pay back the social security. Does that person have to take on a personal part?

There is no legal basis for the individual part of social insurance premium to be paid by the employer, and it should be borne by the laborer after arbitration.

You can ask the company to pay in advance, and after confirming that the social security meets the arbitration requirements, you can deliver a personal commitment letter to the company. The basis is that the social insurance premiums that employees should pay as stipulated in Article 20 of Several Provisions on Implementing the Social Insurance Law of People's Republic of China (PRC) are withheld and remitted by the employer.

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