Indigo Airline - Money taken for excess baggage even though I booked it as a 6E student

I have booked my ticket as a *E student through the Indigo website Hyderabad to trivandrum (departure **jul **** *.**pm)*E***. They haven't mentioned anything except that we have to show ID proof of school/college that we were studying in.*E student booking had an advantage of *% discount on price & **kg extra baggage allowance.The night before my flight I called indigo call helpline and asked that are they sure that we can take extra luggage and asked if I would not be charged as a *E student .They told me that we can take.I reached the airport, generally like all domestic passengers do * hour before the flight departure time.There was a long long queue.I asked a indigo person and went to the counter which they asked me to. That counter also was filled with people. Some how got through and the woman at the baggage counter weighed my baggage and told me It was ** kg excess. I told them that I booked as a *E student. They told me it has not been reflected in the boarding pass.And then asked me to pay rupees ****. Students do not have money, even if they do they, in my case living far from home i have my expenses.I told them that I can't pay,and told them that I booked through *Estudent in the website. The woman at the money collection counter asked me to talk to the supervisor. I talked to him and he was like "why are these excess baggage people coming to me" and was reckless. I was waiting for a sensible answer and he rudely said"this is just a waste of time, pay and go, otherwise you will miss the flight too". I was really sad for making a decision of taking extra luggage, but I should not be blamed, the Website management, the call centre for not giving a clear information,the company for not giving their customers clear information. I gave what all I had and was left with *** rupees in my hand.Left crying.