Account cancelled due to nonpayment

If your account has been closed, you’ll need to apply for service as a new customer. Of course paying the debt will be required to open a new account. 

There is no such email. Your only option is to pay the account to zero. 

AT&T does not use email for support or for this purpose. You can either go to a corporate store, use a virtual phone number, or borrow a phone to call AT&T

I do not have the money to pay in full. 

Your phone will not work until it’s paid to zero. 

I read on posts that sometimes the collection dept is able to waive the full balance if the Customer pays a portion that they agreed on. Is that possible?

While you can sometimes negotiate with a collection AGENCY once a debt is sold, that is not true of dealing with AT&T's collection department.

An unpaid bill is first handled by AT&Ts collection department.  If they are unable to collect the full debt, it is then 'sold' to an outside collection agency for pennies on the dollar.  They may sell a $200 debt for $50 just to recoup a portion of the debt.  The collection agency hopes to collect the $200 from the customer but might be willing to collect anything over $50.  This is how debt collection works.

If AT&T still holds the debt you will have to call and see what it will take to restore your service.  Most likely it will be paying the debt in full.

If an outside collection agency has bought the debt, you might be able to negotiate.  The bad news is that that would mean your account was closed and applying for new service might be problematic.

The only way to know that is to contact AT&T. Which you aren't doing on a customer populated community forum. Please contact AT&T directly.