Sending, receiving, and organizing email in Outlook.com
I would treat these as phishing, not as genuine Microsoft mail. Microsoft does not send daily emails asking you to pay to upgrade a free Hotmail account, and there is no paid upgrade that keeps a free account working. The fact that changing your communication preferences did not stop them also points to spoofed mail, because that setting only controls genuine Microsoft marketing mail.
I would not click any link in them or pay anything from an email. I would check the sender by hovering over the sender name in Outlook.com, because a spoofed message often shows a different real address behind a Microsoft display name.
For each message, I would select it, then use Report, then Report phishing. That reports the sender to Microsoft. Reporting alone does not block the sender, so I would also block the sender, and if the address keeps changing, I would set up a rule in Outlook.com to move messages with that subject to Junk.
I would also check my account directly, by signing in at account.microsoft.com/services in my browser, not through a link in the email. If no upgrade or payment is due there, the emails are fake.
Microsoft explains how to spot and report these messages here: https://support.microsoft.com/en-us/outlook/mail/phishing-and-suspicious-behavior-in-outlook