Sony headphones - Refund not received for my cancelled order

I placed order on https://shopatsc.com/ for Sony MDR-XB*** On-Ear EXTRA BASS Headphones and made online payment later i had requested for cancellation by contacting contactus@shopatsc.com they also cancelled it **th Sept****. It's already one month over but so far they didn't refunded me for the cancelled order. How many ever times i contact them by phone/e-mail they didn't respond to me. It's really not expected such irresponsible behavior from a eminent company. Compared to money there should be severe action has to be taken care on Sony for such a misbehavior act. It's really tortured me mentally a lot their behavior.