Indian Oil Corporation [IOC] — Showing fuel filled beyond the tank capacity of vehicle and charge accordingly

Address:

Sethi Top Filling Point Pump, Sahastra Dhara Road, Dehradun

I filled Diesel full tank from Sethi Top Filling Point Pump at Sahastra Dhara Road, Dehradun yesterday ie 04/06/2022 at 2133 hours in my XUV 500 vehicle which has a tank capacity of 70 ltr. At the time of filling my vehicle was showing two notches balance of fuel left in the tank. However the system there still showed 68.4 ltrs put into the tank and charged me accordingly.
I wanted to contact the manager and called on his mobile No displayed, but he rudely told me to come back tomorrow. That this is no time to resolve issues. I asked him if he has left the pump open at this hour he should be available to take the complaints too and satisfy any objections of the customer then and there. He disconnected the call and did not take any other calls after that.
I asked the staff if there is any complaint registers, they said there is none. And I have to come back tomorrow only. I have to cancel my plans tomorrow to come back and resolve the issue...because the managers and staff can sell fuel till late night but cannot take Complaints to satisfy any queries of the customer.
While I was writing this complaint on the premises informing the staff, as nobody was forthcoming to allay my doubts... I received a call from the owner on a supervisor's phone. He requested for me not to register the complaint and he will make sure to satisfy my query the next day. I asked him how is it possible that, even taking into account some space extra in tank, but in a specified capacity of 70 ltrs of fuel tank they could fill 68.4 ltrs when my fuel gauge was showing two notches worth of fuel still balance in the tank...that two notches would amount to some fuel atleast. He requested me to not file a complaint, took my mobile number and assured me he will contact me in the morning. Whatever time I am available between my plans he will tie up with me.
However it is already 1730hrs on 05 Jun 2022 now, and even the owner has not bothered to call me. He just assured me in the night to stop me from filing a complaint and conveniently forgot about responding back to prove, what he was assuring to do at that time.
So to summarise...
1. I have major apprehension of being overcharged by atleast 15-20 ltrs of diesel.
2. The staff refused to take any responsibility.
3. The manager was not available on site and when contacted on phone, rudely responded that this is no time to clear observations.
4. When asked about the complaint book to atleast record the complaint in writing, the staff told it was not there, preventing me from registering a written complaint for the record.
5. The owner requested not to register online complaint and he himself would call back next to resolve the issue, but never came back.
6. Why was everybody so adamant for me to come only in the morning to assure me about the correctness of their machines. My apprehension of some tampering has been reinforced as they seemed to be buying time to set the machines right before showing it to me.