State Bank Of India [SBI] — Refund initiated but not received the refund

I have ordered a product from myntra Which is Lino Perros Black belt of amount Rs.336 but the refund has not been credited into my account after 12 days of cancellation (refund initiated on 15th of june). They are saying that they dont have information and to contact bank. When i am contacting the bank the bank says to contact Myntra. they have generated a refund reference number[protected]. I made the paymnet from UPI. Please help me out as no one is helping me in this case. I have two products of the same amount but one is refunded and the other is not . Kindly check this matter and solve this at the earliest.