Unscrew the bezel from a pentagonlight L2

[Flymo]

I have tried everything to unscrew the bezel from a new Pentagonlight L2 HAIII.
(heat, wrench, just everything, boiling water) without succes

and I don't want to leave any kind of marks on it, after the job.

Any suggestions to unsrew that damm bezel ?

I want to unscrew it, because the O-ring is not on his (right) place between the lens and the bezel.

Please help

!!!

Thanks.