Fraud Company, materials supplied is not what is claimed; Synthetic material supplied instead of pure chiffon

I purchased a dress worth Rs. 7311 from Chennaistore.com and they delivered it in about a month. The dress was advertised to be pure 100% chiffon. When the dress arrived, it was a synthetic material . I called up and emailed the customer care of Chennai Store. They claimed it was pure 100% chiffon, I was able to debunk this claim by showing the material to well known cloth merchants and retailers in T.Nagar and Pursaiwalkam in Chennai. When I spoke to customer care again they claimed they cant help me and suggested I speak to the bank through which the transaction was made. They asked me to claim online fraud from the bank. One more thing I noted is, after I had claimed that the product is not pure chiffon, they immediately took down the product, which is quite suspicious. The claim made by Chennaistore is that the product is custom made and they cant resale it to anyone. If it is difficult for them to resale the product, they should be truthful in how they describe the product on the website. Trying to fraud customers this way is unacceptable. I think the reason why they have been able to get away with this is they supply mostly to customers abroad. Either the customers abroad don't have means to check authenticity of the cloth or they are unaware of what is being able to sold to them. Upon speaking to people who have experienced such online issues, they have recommended I file and FIR with the police. I will be doing this shortly. After I mailed them stating that I am going to file an FIR, they offered to refund 25% of the value of the dress. It doesn't make sense though, since the value of the dress (including stitching) is not more that Rs. 2000/-. (As stated by the merchants and retailers of cloth in Chennai). Be wary of what you purchase from this store. I have been cheated. The reviews I am posting are genuine, I have recorded telephone conversations and e-mail communications. I can forward it to anyone if they are interested.