Being Billed for goods not received

I am a member of Leserskring/Leisure Books. Today I received a letter of final demand for R 530 for goods not received. I phoned your call centre during early May to enquire why I have not received my order for the first quarter of this year. I was advised that my parcel was sent to my OLD address in Johannesburg. How this happened I do not know as I changed my address in May last year to Bloemhof and received all my parcels at this address. I was then told by your consultant that the order will have to be recalled and sent to me. I advised the person that I will not pay until I receive my goods. I still have not received my orders only letters for final demand. I want this issue resolved ASAP otherwise I will seek Legal advice. I also will then cancel my subscription and post this on your Facebook wall and report you to the Consumer Ombudsman and the Direct Marketing Association. How I can Pay for goods not received??? EXTREMELY UPSET WITH YOUR BAD SERVICE!! Please also provide me with proof of my instruction to change my address back to Johannesburg.