GoAir — complaint against go air ground staff regarding fraud for extra baggage charge.

I shreetej sharma, my pnr is z7tfwp, i travelled from bengaluru to kolkata on 22nd september, 2020 on flight g8 830. I had extra 9 kgs of luggage with me for which the ground staff at the go air counter charged me 4500+750=5250, but as per the regulation i can travel with a baggage of 20+7kgs, but my cabin luggage was just 1 kgs as i had only one laptop with me, which in total makes it as only 2-3 kgs of extra luggage.
Keeping all that aside, i had paid 5-250 in cash for the extra luggage but the ground staff didn't give me any receipt of the payment done, as i was getting very late for the flight, i had no time to argue with the person for receipt. He told me that i will be getting the receipt over an sms, which i never recieved. And earlier i had requested him a lot to consider my case as i was short on money and i had no cash with me. I gave that person my credit card, but he told me that there is an error in my card, i gave him my other credit card, but he stated the same reason. I told the guy that there might be some issues with your swipe machine. But he started screaming on me. I almost cried at the airport, as i was alone and short on money and was getting very late. At last i called my friend to transfer me the money. I had 2500 cash with me and i had to borrow the remaining from my friend and then withdraw the amount from the atm. The person was very arrogant and didn't provide any help. It's okay if i had to pay for my extra luggage, but i do need a receipt for the same. On the flight i asked the flight attendant if we would get a receipt for the extra luggage and she replied yes. After reaching kolkata airport i contacted the ground staff just after getting off the flight, and i was told to go to belt no. 5 and you'll be assisted by one of the goair representatives, but no one was there to help. Then with the help of the cisf personnel, i went to gate 3c at the go air counter to get a clarification and i was shocked to see that the person has only made a payment of 750 and kept the rest of the cash with him. I am attaching all the proofs which i have and i need the receipt of the luggage that i had checked in which i know go air won't be able to provide as it was not inputted by the person. If that's the case i want a proper compensation and a refund of whatever i had paid extra (4500).
I am a student and this is the way i was treated which is inhumane and this was my first flight with go air and i had the worst flying experience. That person made me cry at the airport, i almost missed my flight. I was charged illegally and no receipt was provided for the payment made. When i asked the person's name he started screaming again.
For all this harrassment i need a proper compensation from go air and also an apology from that person and a strict action should be taken against him.
Please go through the cctv at the bangalore airport and whatever i have stated above will be proved.