You must learn to use the simplest trading method. You are probably trying to sell at a price above the current market price and that's why only the cancel option appears. Try changing the price and be careful not to rush it. If it reaches the price you want, you can convert it to USDT or anything else you want. As far as I understand, the reason why it says cancel is because the operation you want to do has not taken place yet. Please watch a few videos about trading and make no mistake.
From what I can see between 1-3, he thought he had it, but he never actually had it. If the trade is still open that means he never bought it, it wasn't on his account, he opened a trade to buy it, but the price went up before he could, so he never did. So that means he used his money to buy something, put up an order, never bought it, in order to buy something you need to click market price, that guarantees that you buy it.
That's what OP should do, he didn't even come to sell option, he wasn't selling anything he had, he was failing to buy, when he cancels he cancels the buy order, and that's the issue. I know it's a simple think for all of us here because we are so used to it, but the reality is that we are not really shocked about newbies who does these, they are learning.