RTO India — Complaint about false fine

Address:

House no 0469, Sainikpuri khaprail, Siliguri,West Bengal, Pin-734009

I took the delivery of my car on 28th June and the showroom has submitted the ARTO on the same day. But on 8th July when I was going to a nearby place in my car, the ARTO staff stopped me and seized my vehicle documents.
They stated the reason that my car registration is pending.
It has been more than 10 days since the delivery of my car but they have not approved my registration and now they seized my documents. And charged me 6500 rupees.
Whose fault is this? Why I bought the car? To keep it at home?