Indian oil petrol pump NERUL LP experience

I am suspicious about the fuel filling at the Indian oil pump at Nerul LP opposite the DY Patil college. Has anyone faced any issue? Today I asked for full tank petrol and the guy filled for 500 first as if I had asked for only Rs.500. Then he apologised when I said again full tank. Then another guy also came and both these staff got with me into to some random conversation and immediately when I looked at the meter it was already reading 900 and finally I had to pay rs 3800 (500+3300) for full tank from reserve. I am doubtful if they made the dial zero when the second filling was done. Any such experiences? I usually pay around 3400 for full tank from reserve.