Delete AT&T Account - Not a Customer

" Customer Service refused to delete the account multiple times."

Then file an FCC complaint.

What account are you talking about?

Why would you have to monitor it?

It is going to do something naughty?

They keep record you had an account with them. They don't forget you were ever a customer just because you've requested it. It is not so much customer is refusing to do what you want as much as they cannot do it.

If you've canceled service, then your account isn't active as you're not paying for anything.

I should not be able to log into AT&T website and access closed/inactive/cancelled accounts. I have had several internet and phone provides that I’ve cancelled and I cannot log in to their websites as a customer because I’m not. It’s not about record keeping. It’s about keeping log in information linked to customers who aren’t actually customers. They can keep minimal records to identify customers without putting people at risk of identify theft. And yes, if you have a login/account you should monitor it to ensure it is safeguarded (two factor authentication). I should not need to safeguard a login with a company I am not doing business with…. 

If you live in California, the CCPA might assist you, otherwise...