UNSOLVED dark photos. when lights turned off at venue

[bobfunland]

HI, did an event tonight and the photos were fine at the beginning (lights in venue on but when they turned the lights off, all the pictures were really dark, I have a camera spotlight on top of the magic mirror but none around the sides. Help please? Client is going to ask for their money back.

Also some of the photos are blurry even though the people dont move much.

thank you