DHL Express India — Duty scams

I purchased a product Raspberry pi from a USA website for my personal use which cost me approx 7500 inr + dhl delivery charges.
Now when product landed here in India dhl message me that I have to pay custom duty of 7200 inr custom duty and taxes, but when you check Indian laws you will see that taxes on these products is no more than 18%.
The amount they asking me to pay is even higher than the actual product price in India.
And also they acted on behalf of me without my permission, they should have asked me if I want to pay duty or not, but instead they paid the amount on my behalf and now forcing me to pay.
I want to file a complaint legally with police and take this company down.
#noScamsinIndia