Crap CommSec system

Was first in the queue to buy some shares this morning. A third of my order was filled before the sp moved above my bid price. Later the sp moved back to my bid price and more shares were sold but not to me, even though I was first in the queue, Rang CommSec to find out how to be told that their current system allows bidders at Chi-x to jump the queue. You may know this I did’t and I think that system is poor and unfair.