Thank you for your answer. The fact that yahoo mail associates a telephone number with the email "***@***", does this that the account exists? Or does it mean that the account did exist? If I post an email to this address, I get a mail not delivered reply, which seems to suggest that the address does not exist. However, the fact that a telephone number is associated with the address seems to suggest that it does, or did, exist. Firstly, does the not delivered reply indicate that the email does not exist? If so, does the fact that yahoo associates the address with a telephone number indicate that the address did exist in the past. Basically, I cannot recall whether I ever had a yahoo email address. In fact, I'm pretty sure that I didn't. If ***@*** does or did exist, I need to prove that it is not my email address. Can I get proof that this email does or does not exist, or did exist?