Stanley® Surform® Replacement Blade

Dear Stanley, THIS ITEM 21-299, does NOT fit on my brand new Stanley Frames. I DON'T KNOW, but the 21-299 I recently purchased with two other of the tools. DOES NOT FIT! My best guess it the pieces that are welded on that should catch and fit on the tool. (frame)? Are too small or “short” and would not catch and create the connection like the flat blades do. I would suggest adding some length (height ?) to them so the securely lock onto the frame. or at least adding a screw (or pin?) that would hold the non-moving end in place. I am highly disappointed in these. In addition to the fit problem, the brand new blade “shattered” into two pieces when dropped on my shop floor. NO, It was not under tension and NO, it only fell when it slipped off my bench when I was trying to install it. Respectfully