Hi guys just wondering if someone may be able to shed some light...

Hi guys just wondering if someone may be able to shed some light for me please.
I am with Commsec and was looking at the premarket on Friday, and noticed that LCT looked likely to open approx 85% down. I beleived this would be oversold so tried several times to place an order between 2.5c and 3.0c only to be knocked back by comsec, as the previous close was too far away. I finally got in with an at market order after open at 3.2c.
Ok I made money on the trade but it was not as much as it should have been.
My question is how do others place their orders at such a low price when I was denied?