Returning from active, time to settle my account. What do I do now?

Without going into much detail, I have been away unexpectedly for approximately 4 years on active duty.  I have returned and am trying to get my paperwork in order.  I know I owe money to ATT for internet, I assume its been sent to collections. My bank is of little help and offers me no collections agencies. I would switch banks but its complicated.  I am working on my credit score and would rather just settle with ATT directly. The generic call center is of no use to me.

Due to the nature of my work, I have very few options. I have the money to pay my bill but the call center is being very difficult. How do I go about settling a delinquint account from approximately four years ago?

Thank you in advance.