Ok that makes more sense, placed order to sell at the current price at the time of $8979 this morning and price has dropped a good bit since then
So I'm going to guess you didn't use a market order, as that would have made the trade go through instantly. You most likely went to trying to use some sort of limit order ( or something of that nature) and your trade didn't go through as the market moved around.
Could we see exactly what your order looks like in order to further help ya out with this problem. Wouldn't want someone trying to buy / sell 13 btc and it not work for them!