Can you post a picture
@Shut Up Legs?
I recently got the Volt 800, graduating from a CatEye Opticube, then a Volt 100.
They all fit on the same, sturdy, adaptable to different thickness of bike bars, bracket.
Mind, there are two versions of the Volt range, the one held by the rubber band is "CX", while the one with the sturdy fitting is not "CX"
Examples of "CX" fitting
here
Example of standard fitting
here
The CX range is typically a few pounds cheaper than the same light that comes with the proper bracket.
The light itself is excellent, so either return yours for another with the better bracket, or fit a shim underneath the light to stop it moving.
Bracket fitting is much better, you just slide the light on and off the bike.