Dear @bpant
In your case where you are being denied by the staff of Air India to carry a toy gun, as you have already lodged your complaint with Air India and its nodal officers and Appellate Officers., you can now file your complaint against Air India to the Airsewa Nodal Officer of the Ministry of Civil Aviation, Government of India.
If you have not escalated your complaints to the Appellate Authority of Air India, first escalate it to the official through their official website or provided contact details such as phone number and email.
Finally, you can also lodge a public grievance to the Directorate General of Civil Aviation (DGCA) to get help regarding this disputed matter of flight passenger rights and security.