Feel Cheated out of a special.

On the 2nd of December I ordered 3 x 1.6kg Rage impact whey online on a special, o. The 6tb of December iI was notified thet my order can not be fullfilled. On the 7th of December I repeated my Order at a significantly higher price and within 21 minutes notified its being picked.

How could my order not be processed at the special price but indeed on the higher price?

Biogens service has to date been outstanding, however this last order leaves a bad taste.