Today I went to Sindu IOC petrol bunk in Girinagar, Seetha Circle. Even though I told Rs.1000, the guy said he heard it as Rs.200 and he has already filled it (It is what the previous guy had filled). Then when I said it is Rs.1000, he filled for Rs.800. I got a doubt and asked for complaint book - he immediately gave back Rs.200. I went and talked to the manager. The manager just called me back and filled for Rs.200. I told him that I don't need any petrol for which I am not paying, but want the complaint book - but he insisted I leave as he has filled me free petrol for Rs.200. Looks like everyone is involved.
I just searched and found a post of exactly the same way of cheating in the petrol bunk in 2011 - http://www.consumercourt.in/product-services/73179-cheating-ibp-petrol-bunk-near-seetha-circle-girinagar-bangalore.html
So this has been systematically happening in this petrol bunk for quite some time now. IOC should seriously think of changing the ownership - if they are really worried about their brand.