I have a private chat dialog between me and other user, and if I delete the dialog (using RestAPI) the chat is no more listed, as expected, but if the other user send a message in this dialog, I receive the push message. Is there a way to stop receiving pushes, or doing other process to remove myself from this dialog?
It's actually normal behaviour.
When, after the private dialog deletion, your opponent sends new message - this dialog will be restored for you.
This is an expected behaviour because you just deleted dialog, but not blocked this user, so conversation should be restored if your opponent or you send new message to this private chat.