Is it illegal for the company to refuse to apply for social security cards for employees?

It is illegal. Social insurance belongs to the compulsory insurance of the state, and any unit or individual that establishes labor relations must participate. In this regard, the seventh paragraph of Article 17 of the Labor Contract Law clearly stipulates.

Because the fourth paragraph of Article 19 of the Labor Contract Law clearly stipulates that "the probation period is included in the term of the labor contract". Therefore, it is illegal for the company not to pay social insurance for you according to the regulations, and it should be paid back.

Failure to pay social insurance according to law is a labor dispute, which can be solved by reporting to the labor inspection department, requesting intervention in the investigation, or directly applying to the labor dispute arbitration Committee for arbitration.

Failure to pay the housing accumulation fund for you according to law is not a labor dispute. You can report to the housing provident fund management center and ask for intervention in the investigation to safeguard your legitimate rights and interests.

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