Indian Oil Corporation [IOC] — employee cheated us

Address:

Hyderabad, Andhra Pradesh, 500081

Yesterday night (24th april 2018), i have filled petrol in indian oil petrol pump (Address: 21, hitech city main rd, huda techno enclave, hitec city, phase 2, hitec city, hyderabad, telangana 500081).
I asked to fill the petrol of rs.200 in my car, and that guy filled for rs.300. When i reconfirmed about for how much you filled the petrol?, then that guy again set the machine for rs.400 without asking me, and then i asked to stop the machine. I asked him that why did you fill this much petrol, then he said that ma'm you asked to fill the petrol for rs.700, 800 or 1000.
That guy cheated us. And was saying that i confused him. Many of the employees in indial oil petrol pump of hyderabad are cheaters.

I faced this problem earlier as well. Either they never listen to what customer is saying or else they really want to cheat customers.