Window installation and product faulty

Mr Graeme Woodberg installed a double glazed window in our apartment on request. After the first rains in Cape Town the window proved not be sealed or installed correctly, the window latch was broken from the start at installation. One year later one small double glazed window started collecting rain in between the panes. It is not sealed and the two panes are separating from each other. Mr Woodberg's response, service and repairs are extensively delayed. Correspondence started in April this year, April the 29th 2015, with the mention of Hello Peter, Mr Woodberg eventually came to seal the window from the outside on the 6th of October. It took 6 months for him to respond. He promised to replace the small window mentioned above, which requires replacement on that day. I checked with him and he assured me via Whats App that he was dropping on the afternoon of the 6th October, to date Mr Woodberg has not responded or come to replace the window. He did not make contact with me and ignored my further requests to attend to the matter.