Problem
I've noticed a common pattern in my interactions. A person—whether a coworker, relative, or acquaintance—makes an offer or request. I politely and respectfully decline, explaining why it's unacceptable, and usually offer an alternative or try to negotiate. The person doesn't argue, negotiate, or engage in any discussion; they simply walk away. Later, they come back with the same offer or request, as if I hadn't explained anything. I decline again, and this cycle continues, sometimes for several rounds, without any progress towards a deal.
Example 1
A couple of years ago, a potential employer in a European country offered me a job. I respectfully declined, explaining that my current job was better for me both career-wise and financially. I also mentioned that I would consider his offer if it included a substantially higher pay. He didn't seem offended and didn't counter my arguments.
However, since then, he has been emailing me twice a year with the same offer (adjusted merely for inflation) and asking if I've changed my mind. Each time, he emphasizes various benefits of working for him but doesn't directly address my reasons for refusal. I've always responded with a polite no, briefly repeating my reasons and inviting him to discuss the pay, but he ignores that.
I believe we could negotiate a mutually beneficial deal, but he appears to be blindly stuck to his original offer and unwilling to discuss his reasons for not changing it.
Example 2
My parents told me they plan to leave their entire estate to my brother because they believe he will need it more (see this post for details). As a result, I stopped talking with them, leaving email as the only option for contact. I stopped giving them psychological support and any kind of advice. I explained that any interaction with them would remind me of their utterly unfair decision. I also told them to turn to my brother for any help.
Despite my explanation, my parents have been bombarding me with requests to restore the relationship and help them with advice. My mother has a complicated medical condition, with doctors offering conflicting opinions and different treatment options. Unable to navigate the medical information on their own, my parents want my advice. I have reiterated my reason for refusal multiple times, but they just ignore it and repeat their requests.
Without my advice, my mother underwent a surgery that later proved to be unnecessary, and her condition substantially deteriorated as a result. Even now, struggling with aggravated health issues and needing my advice and support even more, my parents are still unwilling to reconsider or even discuss their decision to leave everything to my brother. They don't challenge my view that their decision is unfair. Instead, they send emails like, "Think how much time and effort we invested in you when you were a child," and "How could you not want to help even a little bit." They have also tried to change my mind by involving relatives and even a coworker of mine (by sending her a message).
Additional remarks
These examples are not isolated exceptions. Even a close friend repeatedly asks me to rent a flat together to save money, unable to accept my reason for saying no (which is that privacy is important to me).
I must be doing something wrong, but I have no idea what it is. I've asked a couple of friends, but they couldn't provide useful feedback.
Question
What am I doing wrong? How do I stop people from repeating the same offer or request over and over again? How do I make them understand that their original offer or request is unacceptable to me, no matter how many times they repeat it? How do I make them take my reasons for refusal seriously? How do I get them to choose between engaging in a real discussion or negotiation and simply leaving me alone?