Blinkit — Regarding return policy

I made a purchase today of women's shoes for 2 different sizes to avoid last minute hassle.
When the product where delivered to me they didn't had any tag attached to it. But when returning the product its asking for tags. How can I present a tag when its not there?
Now they are denying the return or refund.
It is a clear fraud case where customer is not made aware of the policy and the shopkeeper sends a pair of shoes without the tag and then the customer suffers for it.