Is the kickback from the cost consulting company legal?

Illegal. According to the inquiry of China Travel Service. Com, the people who accept kickbacks are state employees, employees of companies, enterprises or other units, or personnel of state organs, state-owned companies, enterprises, institutions and people's organizations, and objectively must take advantage of their positions to accept kickbacks; Accepting kickbacks constitutes the crime of accepting bribes, and it must reach the amount required for the establishment of the crime of accepting bribes; Fourthly, accepting kickbacks as a subjective element of bribery is the same as that of ordinary bribery crimes, both intentional and illegal.