HOW DO I MAKE A COMPLAINT ABOUT ITEM THAT HASNT ARRIVED, THAT WAS PURCHASED MORE THAN 45 DAYS AGO

[lauratownsend55rocks]

I PURCHASED AN ITEM (W767310736289618) PAID FOR ON 2/9/13.  THIS ITEM HAS NOT ARRIVED AFTER FIVE MESSAGES TO SELLER, THE SELLER ADVISED THEY WOULD SEND THE ITEM WITH MY NEXT PURCHASE FROM THEM. THIS IS RIDICULOUS AS I WILL NEVER BUY FROM THIS SELLER AGAIN. IT IS NOT EASY TO MAKE COMPLAINTS IF THE ITEM WAS PURCHASED MORE THAN 45 DAYS AGO, IF I DO NOT GET RESULTS FROM THIS MESSAGE I WILL MAKE A FORMAL COMPLAINT WITH THE AUSTRALIAN CONSUMER AFFAIRS, IT IS ONLY A SMALL AMOUNT OF MONEY SO I DONT CARE ABOUT THE MONEY BUT I WILL NOT BE STOLEN FROM ESPECIALLY WHEN EBAY PROMISES SECURITY. VERY DISSAPOINTED WITH THE SELLER AND WITH EBAY, WHY DOES EBAY MAKE IT SO DIFFICULT TO CONTACT SOMEONE WHO CAN HELP??????