Camper Boots Size Mismatch! Left 39, Right 40 Causes Walking Issues

I recently purchased Camper boots, but there's a size discrepancy between the left and right foot! There's a problem with the product. I wore them for only two days (on February 7, 2024, and February 8, 2024). Upon receiving the product, I checked the sizes immediately. I thought maybe different sizes were mistakenly placed due to oversight. To my surprise, they were the same, no issue there. On the first day, I felt a difference but didn't dwell on it much. By evening, my foot was swollen, and I attributed it to fatigue. There's no problem with the left foot (I'm sure it's size 39), but the right foot is size 40. My foot keeps slipping inside the boot, causing inconvenience while walking. Despite repeatedly contacting Camper to exchange for size 39, they haven't responded at all, neither positively nor negatively. Even small local businesses respond within three days, making it incredibly frustrating for Europe's largest shoe brand to behave like this. I'm deeply disappointed.