Paytm — wrong product and not refunding

Address:

Kutch, Gujarat

I have ordered xiomi mi power bank of 5200mah. Instead of that i received a power bank of xiomi mi 10400mah. But its useless. They sent me a cheap product. Which cannot charge one mobile completly. Aftr makin many complains they are not giving me any response. I am very disappointed by this. I have all the images and screen shots of order. I returned the product to merchant but still no refund its been more than 15 days. I want my money back from paytm anyhow.