Rebellious 7year old

Totally at loss for my 7year old. She has been persistently misbehaving not listening to what we say like if we are getting late for school(I have to go to work after dropping them) she won't get ready and today she took her water in coffee cup!! She lost her water bottle and I gave her another beautiful one(I always have replacement incase they miss) but she totally refused to. She won't study she won't help in anything and does what she wants all the time and if I insist she would misbehave. Her elder sister is quite the opposite, she always finishes her study work on time and gets late to school because of her. My husband is no help either he would start fighting with me or blame me if anything happens in front of the kids while I'm trying to deal with her as best as I can. I can't do much about him either at present. Please any advice is welcome.

P. S she is a sweetheart otherwise loves me loves her sisters