List of activities you are allowed to do in Indonesia with Index C visa:

This type of visa is not suitable for work, if you intend to work in Indonesia, you will need to apply for the e-Visa index c311 or c312. 

Please apply for a visa according to the purpose of your activities in Indonesia. Discrepancies in the use of visas and activities may be criminally imposed as stipulated in articles 118 and 123 of Law No. 6 of 2011 on immigration. Criminal provisions may ensnare guarantors and/or foreigners.