Bigbazar/nike
Egretting to change the product under warranty

I purchased nike sandal from big bazar.. inderlok on 5-august nd made the payment through credit card...

they had given me waranty of 3months..

now tat sandals got..damged and i lost..the bill of tat..also

as today on 10-october whn i visited the shop..and asked for changing... the sandals..

they refused me to change... without the bill

wat should i do now...