Big Bazaar / Futurebazaar / Future Retail / Hometown — wrongly charge for packaging bag..

Address: ambience tower, sector-10 rohini, New Delhi, Delhi, 110085

I was overcharged for packaging bag..
After shopping of goods in big bazaar... They forced me to buy packaging bags too.. For rupee 18 each.
As requirement they forced me to buy two bags total of ruppee 36.
I am attaching bills for bags please see he matter.

As my knowledge retailers can't charge customers for packing bag