Can't get access to my outlook after being blocked out by 'too many' security checks

Hello, I have been locked out of my Microsoft account following 'too many security check requests'. I was prompted to do the checks (not my decision) because if I cancelled my old phone number is linked to the accout. I was supposed to be able to still have access to my account despite the security check changes and now I'm blocked. I really need urgent access to my emails and cannot wait until 29 September.  Please can someone help? Thanks!