Ford India — Stole Diesel from my car

Hello,

Today on 10th March I submitted my vehicle to the authorized ford service center.
When I got there to pick my car up I saw that my diesel was almost empty while when I submitted the car it was a full tank

Now I am thinking that these guys are thieves and they might have replaced my car parts with the faulty ones as well

I need the complete refund for my diesel and the mental torture they have given me.