If the picture is consistently misexposed, then the exposure-compensation
control (assuming the camera has one) should fix the problem.

Compensation doesn't fix the problem, it fixes the symptom. The problem
remains.

The compensation range on this camera is +/- 2 stops and this is not enough.

If it doesn't, then the camera needs repair or replacement.

I'm asking questions to find out what the cause is. Repair options to be
considered after this is determined.

Thanks.