If I put in an order for 10000 shares for 2-3 days and it gets filled 4000 one day and 6000 the next , they charge me 19.98 for the trade 9.99 each day.

I don't want to stir the pot, and I am not 100% sure of my footing, but I cannot recall being charged more than $9.99 if my order took more than 1 day to fill, and it was filled in dribs and drabs.