Myntra.com — Courier boy charged twice.

I ordered a Shirt from Myntra. The courier boy came and i first tried to make payment via google pay, but the payment went on processing(which sometimes happens in Google pay). So courier boy demanded cash saying that amount via google pay will get refunded to me back. So i paid him cash. The next day i found that payment via google pay got processed and was successful. Thus i ended up paying twice for my order. I then called courier boy for refund, he said it will get refunded by myntra. So i requested myntra but myntra rejected my request. Then courier boy said he will get my money back but it has been 2 months almost now, and i haven't received the extra amount that i paid.