Unsatisfied complaint resolution

I ordered a Corn & cheese waffle at Woolworths Food restaurant/coffee shop on Thurs, 28 Jan 2016. I ordered this specific item because I had the same the previous Fri (22 Jan) and loved it. I was specifically impressed with the amount of avocado that was served on the corn waffle. Today, 29 Jan 2016, I complained to the Manager regarding the amount of avo. It did not even cover half of the waffle (last time it covered the entire waffle & more!). I asked that they just bring me extra avo. She came back from the kitchen with a long explanation re the sizes of avos, the scarcity and that the kitchen staff claim that I'm maybe confusing this item with the Frittafle (which I have never had before). As the avo changes the entire taste of the meal, I said they should still provide me with extra avo, explanations and all. I'm paying the same amount for a meal that has approx a 1/4 of one of the elements and no one advised that it is out of stock or less than usual. I would have ordered something totally different. She then said the kitchen staff said they will not provide me with more and that settles it. She was being very sweet about it, but I'm left unsatisfied and had to pay in full.