How to turn off

Hold down the button for a few seconds

I didnt but this didnt work.  Should this work, maybe we are not holding down the power button long enough.  thank you for replying to my question.

hold it down for about 5 seconds

Hi, the light is still on. Holding down the power button is not turning the light off.  Any other suggestions?

One my collegues called Strker and they meantioned that the transformer  might need to replaced.

Have you tried a complete reset by removing power to the light?  I.e, turn the breaker off.