SpiceJet — Charging 1000 for rs 150 bag

I dr sehrish travelling from del to sxr via spuce jet airline Sg8963 was asked to pay 1000 rupees extra bcoz I had extra bag. Although we were 2 passengers and total weight was 21 kg. Y was I asked to pay for a polythene bag. That was not even a suit case. Despite a person b4 me had 35 kgs that too an individual was allowed to pass without any charges. Y unfair? And y I had to pay for a polythene bag that contains mere frocks of 2 year old jus to avoid shimmer mess I kept in that bag. R u people going to pay for any disturbance in the shimmer. I hope u people r ready to pay me 5000 rupess if my frocks had even a little mess.