What's an utterly selfish bitch 1 day I was coming back with heavy bag of shopping and she said to me, would you like me to help you carry that up the stairs? And I said, no, why would I flaming? Well, want her to help me carry the bag. And yet when it comes to the bin, oh no oh no oo
TBH, this all sounds like a joke, but if it’s not your quote above answers your question. Your neighbour offered to help you carry your shopping and you grumpily said No. So why are you surprised she didn’t offer to move your bin? The answer is because she thought you’d snap her head off!
That’s also why she’s spoken to you about how you position your bin outside - because she’s nervous about moving it herself. Why don’t you just leave space for her bin??
Why does it bother you if the landing window outside the flats is opened by her? Unless she’s leaving it open overnight and it’s a security risk, leave her alone. It’s boiling hot and she’s probably trying to cool the landing and keep it fresh.
You also mention that previously you’d taken all 3 bins down but had stopped doing that as your neighbours hadn’t reciprocated. Why worry? Ignoring this neighbour you don’t like, it’s clear that all your other neighbours just want their own stuff and to be responsible for it. You’re in separate flats not a house share.
You sound rude and grumpy. This new neighbour was brave enough to politely ask you to do something. I bet that your previous neighbours didn’t want to approach you and so, yes, did move your bin themselves, but probably cursed you as they did.
Simple solution - place your bin more thoughtfully and stop being so bad-tempered towards your neighbour. She’s done nothing wrong. In fact, she’s treated you with kindness by offering to help carry your shopping, and she’s treated you with respect by asking you to place your bin properly rather than just moving it herself. She’s making every effort, you’re making zero.