Adding email address to current account that is associated with a deleted account

My personal email is attached to an unused box account. I wanted to add personal email address to my primary account. I incorrectly assumed that deleting the unused account would free up my personal email address-when I tried to link it to the primary account, it showed it was still assigned to an account. I then searched the forum and found the 120 day rule but also a shortcut - that I should reactivate the deactivated account, assign a 3rd email address to it then delete personal email address which should free personal email address to be linked to primary account. Unfortunately, for some reason, I am unable to reactivate the personal email box account. There was a message to call billing support (that is a free acct?), which I did and they directed me to submit a support ticket. The person on the support line directed me to the ticket page but when I couldn't see the "submit" option, he asked me to completely log out (which I did) and then I was able to see "submit" but the trouble ticket I received in my email said that since it was submitted outside of an account log in, it may take several days longer to receive a response. All I need is my personal email address to be freed up so I can attached it to the primary account. Thank you kindly!