unable to receive security code

The telephone number listed on my account is outdated.  When I try to change it, as well as other pertinent information on the account (i.e. it's time for my annual pymt) I receive instruction that for security reasons they first need to text or call me with a security code.....but of course I don't have that telephone number anymore. When I call Microsoft, I receive a recording that tells me I don't have access to customer service (SIGH).