Police forced me to pay on spot

Location: BTM layout, Bangalore. Under control of MICO police station.
I was not wearing helmet. The police caught me and asked me to pay the fine on spot.
They refused to give me an e-challan.
They also threatened that my bike will be taken to police station.
So i had to pay on spot.

Now I want to acknowledge the police station that this incident should have been handled differently and may be fine them back or atleast get an apology letter from the police who fine me.

How do i reach them and what is the procedure?

Dear @yashwanth_cb

To report misconduct by police at MICO Police Station, BTM Layout, visit the station in person or contact the Bengaluru City Police Public Grievance Cell. You can also file an online complaint via the Karnataka State Police portal or email to the police commissioner detailing the incident, date, and officer’s details if known. Keep payment proof for reference and request a formal inquiry or apology.

If still need help, reply to us.