<..> What is it really impossible to write posts from a new account? <...>
According to the forum rules, banned user is not allowed to write posts except appeal topic in Meta, until the ban will be lifted.
25. Ban evasion (using or creating accounts while one of your accounts is banned) is not allowed. ~
If you get banned (temporarily or permanently) and create a new account to continue posting / sending PMs, it's considered ban evasion. The only exception is creating a thread in Meta about your ban.
Thank. Now it’s clear why they blocked my 2nd account (SamDummy_Unban_Appeal). Honestly, I did not plan to use it. But my first account was never unblocked and I was tired of waiting. I believe that plagiarism there is just a mistake (my mistake), and it’s not worth it to block the normal user account. People write to me, ask questions, but I can not answer them.
You've already shown that you'll continue neglecting the forum rules by opening a new account, and continuing to post on it even though you've been banned. That account was likely banned for ban evasion. If there's an email within the banned message then email that with your ban appeal. However, if it was for plagiarism they are unlikely to be unbanned.
I sent several times.
Most likely for plagiarism.
But what plagiarism can be in a simple message, without explicit claims for authorship of the used copied piece of text. Yes, if you approach formally - this is plagiarism. But if you look, and wonder why do I need it? It becomes clear that I do not need it. I understand if it was a separate topic, then I would agree that I was wrong.
In general, some offensive things are happening.