Airtel — overcharging on 4g hotspot

Address:

560004

There is an airtel express store near by my area. When i inquired about buying a 4g hotspot, the store keeper said it costs rs2710. When i paid the amount and got the box i notice that mrp on the box was rs2500. When asked about why he took the extra amount, first he said it is gst. After i clarifying that gst should be included in the mrp, he said it is the dealer commission. I was surprised to hear that so i demanded a bill for that but the store keeper was reluctant to provide one. I became supicious by his act so decided not to buy the hotspot. I took the money back by returning the box.
Further, on the same occasion (Prior to buying the hotspot) he charged rs150 for a new 4g pre-paid sim. I'm not sure how much is the actual cost but i doubt it is rs150.

I request you to advice the store keeper not to demand extra cost from customers.

Here is the store address:
No 37/1, ground floor, subbarama chetty road, near dental care, basavanagudi, bangalore, pin: 560004