英国采购需求：铝窗，铝幕墙，铝凉亭，铝栏杆，铝甲板栏杆，Westbury 铝栏杆

We've encountered some issues with the bifold doors we've received from your production line. Specifically, we've noticed discrepancies in quality that may affect performance and customer satisfaction. Could you please provide us with guidance on how to address these issues? Also, we'd appreciate it if you could share any troubleshooting steps or solutions that could help resolve these problems quickly. Looking forward to your prompt response.