I haven't been able to cancel

It's nuts but I haven't been able to cancel my account. I had recently called to renegotiate my rates and was promised a discount, a month later, it turns out my discount wasn't applied. Called back and was told even though I was promised one, they wouldn't be doing a discount. So I canceled my account. Rep told me it was done. No email confirmation. Rinse and repeat 2 more times. 

Does anyone have an escalation path I can take to actually cancel and get a confirmation? What's happening at att that this is happening with accounts?