Selling my work as her own

I had a lady approach me in regards to selling custom made jewellery that I make from home. I have been making and selling these for quite sometime but it never really appealed to me to go to markets and sit all day waiting for sales. She already has her own business which is different to mine but she does markets each weekend and asked if she can sell my items and the idea was a 60/40 split 60 for me 40 for her but she was able to mark the price up a bit and it ended up being more in her favour than mine, which didn't worry me too much . The problem is I sent her heaps of my items to use as advertising for what I do and so people could see the sort of things I make on the provision that anything that sold of those I got 50% of what she got for them . All went well for a while but she slipped up and let me know that she had sold some of the display pieces I had sent her but I never received any money for those and now it looks like she is using my pieces to advertise work she is going to do herself and cut me out completely.
I found out she had done something similar in the past to someone else she got into business with and used pieces she didn't make herself as advertising for things she was going to make on her Facebook page as well as at the markets and that that lady was threatening legal action. When she was telling me this she told me that as she had bought this other ladies work she was allowed to do with it whatever she liked with it and was within her rights to use it at the markets and on fb. As it looks like its all going the same way with me I'm wondering where I stand? Is she within her rights to use my stuff to sell her own?