I know that is frustrating. I've ran into that problem myself. I have noticed that the local dollar stores are now carrying replacement razor heads (not just whole disposable shavers). Maybe try checking out a local store to see if they have any?
I've also had the problem of products being "redesigned" to be "new and improved". No, not really. I've had this issue with baby wipes and disposable diapers from a few different brands. The "improved" versions are subpar and don't work as well. It's obvious that the materials used are cheaper (wipes are thinner, diapers not as absorbant).