Fashion And You — Unable to provide refund

I purchased a particular product from Fashion and You on 26/12/2015 but due to size issues I wanted to exchange i with another size. When I contacted them, they told me that the product cannot be exchanged but I will get a refund. I had to ship back the product myself as they did not provide any reverse pickup facility. Even though they received the product (which I found out by tracking courier details) there was no sign of a refund or any store credits. After countless mails and warning of complaining about them to legal authorities, they finally gave me credits to buy other products from their website. I found out about the credits by searching my profile in their website as they did not notify me about the credits. I purchased another product with the credits on 27/01/2016 but they did not even ship the product yet. Their service had always been slower than other online shopping companies but this time there are showing signs of fraudulent activity.