Flexus Women's ROSELOUD Slippers

I bought my first pair of these slippers from a seller on eBay and loved them. Wore them almost daily until they started fraying and coming apart. They were a size 38 and a little tight (but not painfully so) in the beginning but they stretched out and became quite comfortable. When I decided to replace them, I went directly to the store and bought four more pair (they were on sale, LOL). I bought two in size 39 and two in size 40 (different colors and different size availability). Both pair of the size 39 were so tight, even after wearing them for over a week every day, that I eventually stopped wearing them. They were so tight they made blisters and left heavy imprints on my feet, especially at the back of my ankle. They caused extreme pain and toe cramping. I started wearing the size 40 slipper, which are so huge they flap around like flip-flops when I walk. How can there be such an enormous difference in size between 39 and 40? And how can 38 fit and feel better than 39? I love the overall design and look of the shoes, but the sizing issues mean I won't be buying any more shoes from Spring Step.