bad quality of Nike sneakers

I bought my sneakers in April 2017 at Shelflife in cape town and noticed that the zip is breaking and the material around the zip area is torn. I went into the store yesterday and spoke to the "general manager" Ashley benn who told me their policy of 3 months with the brand Nike. I wasn't happy and asked him to escalate my complaint. He asked me to take pic and email him which I did. He also said that they will not help me and made it clear but I insisted that he escalats. I emailed him this morning for feedback and he said the same thing in his email as yesterday. Does Nike sneakers really only last for 3 months??? Is the quality gone down??? I know this is a factory fault. The entire sneaker upper is genuine leather but the area around the zip is not. Bad bad very bad. I have Nike sneakers for years and that I wear all the time with nothing wrong. You cannot tell me your quality is this bad. Ashley did not even offer to send the sneaker back to the brand manager for investigation, he just said I cannot leave the sneakers with him.