Can't add/change email: "Oops — that person already has a Box account"

​@community-manager ​- I cannot add/change my email address on my account. It gives me the error:

 “Oops — that person already has a Box account”

even though I deleted the account associated with that email. What do I do? I NEED to change the email on my box account to this other email because the one currently on my account I lost access to.