I'm confused about how you are being charged $12 for free postage. Nearly all her listings are free postage, so if you buy and pay straight away, there can't be any additional costs added. The listings I looked at all had immediate payment required, so she can't add costs after the sale, because unless you pay straight away, there is no sale.
I'm also confused about how you know she would be paying $40 a year for free postage? That makes no sense at all! As for officeworks, all the listings I looked at showed Australia Post. Can you post the item number of the item you bought so we can have a look?
As for the removal of negative feedback, I'm guessing you broke some rules of negative feedback. There are rules, and if you break them, the seller can request to have it removed. If you got abusive, calling them a scammer, or any other word relating to that, calling someone a w*nker (which you did in a neg you left), or mentioning a dispute (I know you didn't open a dispute, but it's good to know that for future reference), plus a number of other things. Given she has a previous negative feedback still visible on her account, I'm guessing you violated the feedback policy.
Can you remember what you wrote for the feedback? Word for word, and whether you put it in uppercase. That way we can see if it violates policy or not. If it doesn't, you can request to have it reinstated.
We regulars here are acutely aware that there are some sellers who deserve negative feedback. However, if that is your intention, leave it a day or 2, until you are feeling less hostile. That way you are more likely to leave factual feedback, rather than emotional. Factual feedback is less likely to be removed.
Oh, and it's not the seller's fault the courier left your parcel where they did. Once she hands it over, she has no control of what happens to it. If that's an issue, take it up with the courier company.
