Nike Air Max Pulse Heel Seam Issue After 5 Months

I bought a pair of Nike Air Max Pulse shoes from the Sneaks Up website, and unfortunately, the heel seam started to come apart after just 5 months of use. Even though I've been extremely careful with the shoes, I'm baffled as to how this could have occurred. I sent the shoes in for warranty service, but I had to personally reach out to customer service to inquire about the status. I didn't receive any SMS or email updates, nor did I receive a notification from the courier service confirming the receipt of my product. Why would a shoe that's only 5 months old start to unravel at the heel seams, even with careful use? I kindly request a prompt resolution to this matter and appropriate compensation for the loss incurred.