I like this one very much except the inner shadows on the butterflies.
Try and show them what they want, sometimes that might put them off. If they still don't get it just cash the money and leave them be. You've done your best, it's not your job to teach people what taste is...
PS One thing that would convince them maybe would be a really bad choice of the colours they suggested. More often than not, the people I know can't tell the difference between a fully saturated orange, and one that has lots of black in it... You get what I mean I hope