How do you set up buyer exclusion zones with domestic post?

[h2o-au]

Im trying to set up buyer exclusion zones for individual listings. When listing the item I can manually do it ie it comes up with exclude NT, TAS and all the other locations etc,  whichI do excluding the zones for my bulky items due to the high postage costs. Thing is last night I sold a bulky item to SA regional and the post was $42 dollars yet I had this litsting on my exclusion zone? So I went and checked all my items that I thought had exclusion zones and even though I had manually entered them on each listing its not applying it to buyers in these zones when listed. I even rang a friend who lives in one of the exclusion zones to see if he could purchase the item and sure enough he could even though i had excluded his location manually when listing the item? Have contacted ebay they seem to think it may be a technichal issue and have offered the solution of making it for all my listings in my settings which isnt viable for obvious reasons due to some items are under 500 grams hence I dont want $20 post on them. i want to be able to do it for individual listings. Any help would be appreciated. I have also tried the advanced listing tool to no avail. Beggining to think there is a glitch with my account. Thanks in advance.