Worst service ever!!!

I bought a pair of jeans online, after they were delivered I noticed that the order was wrong. I notified them and they sent a courier to pick the parcel up, that was in the beginning of July, and till today they dont want to refund the money back. Inspoke to numerous call centre agent and their forever changing time frames came and went and nothing has been done. I wasn't expecting this from a "top class" store.