Spotlight plus snapshots at night

I have just purchased a spotlight and mounted it on the back of the house. I turned on the snapshot feature and keep getting black images which i think is a bit pointless and not exactly what i thought i would get from a camera with night vision. In between my black images i get one night vision image and then a stream of black images again. Ive had 2 calls to support, first time I got to Advanced support and was told the images with visible detail have the light on and the others do not! When I turn the light on the bricks of the house appear red the images are just black and white so i dont believe the support assistant i think the night viaion works some times. My second call to support result in someone on first line telling me black images are what it does when theres no external light! Again this is a nightvision camera so why would it only produce a black image? Last night I got approx 10 consecutive snapshot images in full night vision detail followed by 1 black image and then a few more night vision snaps so i think this camera is faulty. Can anyone share their experience with the snapshot feature at night in a dark environment on this new spotlight plus camera? Thanks in advance.