Indian Oil Corporation [IOC] — forgery in filling petrol

Address:

Chennai, Tamil Nadu, 600100

Dear sir/mam,
On 17-nov-2017, as i was trying to fill petrol for rs.1000 in indian oil petrol bunk, they cheated me, as initially they filled only for rs.300 (Rs 301 approx) manually, & other person was distracting me that my credit card is not working in that. When i was trying to explain that i asked them clearly to fill petrol for rs.1000, then he told that he will add rs.700 more.
And he filled the mark rs.700 from rs.300 only. Two of my friends from my car too watched the same. But they argued me that they started from zero point.
As i know how to pay in card payment machine, i checked it & was working fine. After deducting my rs.1000, they filled only for total rs. 700 only (Ie from "0 to 300" & "300 to 700" respectively)
Bunk: "lakshmikanthan service station", 323/2, velachery main road, pallikaranai, chennai 600 100.
I request if you can necessary steps/actions with the respective employees at that bunk.
Pfa the bill soft copy.
Regards,
Lenin