I have had it happen to me as well. Not a funeral, which would be worse, but at Christmas time a few years ago. My SIL sent a photo to say thank you for the arrangement, but honestly, it was a few evergreen branches and fake berries. I had paid quite a bit, and was embarrassed. I think she would not normally have sent a photo, but it was her subtle way of letting me know I wasn't getting value, without actually telling me the 'flower arrangement' had no flowers at all!
I called the florist to let them know, and they offered me a discount on my next arrangement... as if I would ever use them again.