Account for book not received

On the 27th of August I saw on Leisure hours website that a book was sent to me on 20th of July 2015, which I have not received. I sent a mail to them, saying I definitely did not receive the book. they responded that it takes 20 working days to receive a parcel, according to me by the 27th of August it was already more than 20 working days. The parcel isn't even traceable on the tracking service! They even have the flippen audacity to tell me I need to track a parcel that THEY sent. Well, dear Leisure Hour, I will not pay for a book not received for me. I am ending my membership with you, as this is the type of service that made me resign before, and it has not improved. I will not pay the amount of R165 for a lost parcel, or goods delivered elsewhere.