[Resolved]  Indigo Airlines — customer grievance regarding excess baggage in indigo airlines

I am student of IIT Kharagpur and frequent flyer of Indigo Airlines. Today morning I was flying by Indigo flight 6E 874 from Bangalore to Kolkata. My PNR was KGS5PQ. I was returning to college after my vacations and my combined baggage weight including the laptop was 3 Kgs over the specified weight. I requested and pleaded the counter executive to give me a levy to carry my excess baggage. However she was rude and didn't allow me to meet her supervisor with whom I could plead my case. She has issued me a payment receipt with receipt number 1639500 with the total amounting to INR 900.
There have been many instances where people have been allowed to carry upto 3 Kgs of excess baggage under special circumstances. Doesn't my case come under a special circumstance?
Being a frequent flyer and a student I am indignant, shouldn't I be allowed that much as a loyal customer?
The matter should be looked into by appropriate authorities and resolve the issue by providing a refund to me at he earliest.