Skybags website promise to refund or replace item

I bought sky bags (Candy 03 blue backpack) from website skybags. It came under 3 years limited international warranty.
I contacted skybag customer care and I say this product is of third class quality and there is a also a zipper problem in the bag.
When i want to return the bag the skybag website told me that they would replace the item but will not give any money (Bag price) as there is money return policy on the website within 21 days, so kindly help me.
Order No.: – 100003064
My mobile No.:- 9990733364
my email id :- [email protected]