need an email or phone to escalate a billing claim

After talking over the phone an chatting with ATT reps, the problem with the billing of my account has not been address properly.

Basically, ATT is not abiding to our agreement. I have the email that they sent me which states everything about the charges and discounts-promotions to apply. However, the discounts have not been applied, the due balance is getting higher, and ATT so far is not willing to accept the terms of the agreed contract.

I think the last resource for me is to make management aware of my situation to get proper help.

Therefore, please provide me with a contact (email or phone) in Corporate Office to escalate my claim.

Regards,

Luis O