Myntra.com — defective product - different size sandals

Complaint for Myntra
Inc.5 Sandals delivered for
Order #[protected]-6238603,
delivered 30-Mar-2019, by Myntra
were of different size each. One 39 and the other 40. On raising a complaint Myntra refused to resolve the issue saying that they need the shoe box which I did not have. I have been duped with wring size products wearing which gave me serious pain in the leg.
I request for a refund or the correct product