Bharat Petroleum [BPCL] — not responding to customer complaints

BPCL is not giving 0.75% discount/cash-back on purchase of oil from petrol pumps i.e. S K rahman & S F rahman. After a number of mails no response from BPCL. Inspite of giving discount rather they are charging more than transaction value. As a result the Customer is suffering from financial loss on each transaction of purchase of petrol. This is a discouraging in the movement of 'digital/cash less India' by Govt of India.
It is interesting that, in some transactions they are giving 0.75% cash back but in some they are not giving. Even there is no clarification received from BPCL on consumer complaints. So the internal control system on providing cash subsidy is weak.