Does anyone have experience with a Shield RMSc?

I have a problem with a Shield RMSc red dot optic that I have on a Glock 34. The optic has the red dot permanently going and this one finally ran out of battery after a couple of years in use. So I popped out the battery slide and replaced the 2032 but now the bugger doesn’t work. I initially thought that I might have put the battery upside down but no. I then thought maybe the replacement 2032 was also flat but four batteries later and it is still not working so I suspect there is something I am not aware of that is at issue.

Has anyone here had a similar experience or can throw some light on what the hell the problem is (or might be)?

Here is a extract from the RMSc manual:

Fitting and removal of the battery:
Battery Fitting: The Reflex Mini Sight Compact uses a 3V Lithium
battery type CR-2032 which under average use can last 2 to
3 years. Replacement is required when the intensity of the dot
appears greatly diminished against a bright background.
To change the battery remove magazine and ensure that the gun
is clear and safe before proceeding and keep the gun pointed
away from you whilst performing the following procedure.
Use the hex wrench to remove mounting screws from the sight
and detach the sight from the gun. Flip the sight upside down to
expose the battery compartment.
When inserted, the positive side (+) of the battery should be
upward and visible. The side of the battery should be pressed
against the contacts before being inserted.
The negative (-) contact must be properly situated in its recess at
the bottom of the battery cavity, should it be bent out of position
it may touch the positive (+) side of the battery, and the LED will
not work.
To remove a battery, use the 1.5mm hex wrench to prise the
battery from its cavity with the wrench placed in the slot, which
is part of one of the forward mount location holes.

Thanks for that. I am pretty sure I have been doing all of that but I will give it another go

Its also a possibliity that the battery never ran out and the optic has shit itself.

best to wear surgical type gloves on battery changing, skin oil is a bastard.
and clean the contacts with alcohol

Thanks guys.