Managing personal Outlook.com account settings, security, and privacy
I am sorry that you lost access to your account and are having to go thru the Microsoft Security Maze with no clear results.
why wasn't the account put into the 30 day security delay when my details were removed by the hacker and their account added ?
Because the hackers had control of your account. To Microsoft Security it just looked like the legitimate owner of the account was making changes. This does not trigger a Pending Request.
why was the 30 day security delay thing triggered when I changed my security settings back to how they were ?
Because at that time you were not the current owner of the account. i.e. You were attempting to take back ownership.
how can I get out of this loop of the hacker just being able to cancel my request to change security details?
If you have gained temporary control of the account (it sounds like you have) then even if the hackers get a notification about a Pending Request, they will not be able to cancel it. Only the person who initiated the Security Change can cancel it.