payment before withdrawal

I met a lady on Facebook by the name of Melinda Siew, she's a trader, we came to an agreement sometime ago that she will do a trade for me when a profit is made I withdraw and gave her 30%. I deposited the money into Luno account and it was transferred to a platform which she sent me a link, it's name is easymarkest.com. she did a trading then tell me that I must not forget about 20% before withdrawal then our dispute started there.