Folding ebike handlebar post box won't stay clipped together

[Kernel]

The quick release of the handlebar post of my Leon NCM London won't stay clipped on (what's the correct term for this?). If I try to ride the bike, the clamping block always comes off the clamp it is clipped onto, even when it is adjusted. I don't think it is supposed to be able to clamp on at full adjustment so I guess the tab on the post is worn out. Please suggest a way I might be able to fix this without replacing the whole handlebar post or please suggest a good replacement part. Thanks!