Myntra.com — refund not received in my bank account

Website:

myntra.com

I bought a suit case from myntra order id[protected]-7370803 but they didn't deliver it and said lost in transit. They have not returned my money also. The bank reference number provided by them is invalid i checked that by bank.
Date of purchase is - 20/12/2018
They initiated refund (According to them on)-4/01/2019- but still i have not received the money.
My registered mail id on myntra is - [protected]@gmail.com