AT&T will not unlock my Samsung Galaxy Note4 . They are holding me and my phone hostage.

Have been a loyal AT&T customer, and as the signal is pretty bad in our new house I have decided to switch over to another service provider.  I have a Samsung Galaxy Note4,  that is bought and we paid off the last 3 instalments lump sum and I'm not on any contract.  Called customer service, tell me I have to put a request in online.  Do that, denied.  This is the response I get using the online request, despite the phone being paid off:  

 This device isn’t eligible to be unlocked now because all of the instalment payments have not been paid.
Log in to your account to check your payoff information and pay the instalments online.
You can submit a new request 24 hours after you make the payment.

 This is the reply I got after waiting for 3 days.

Thank you for contacting AT&T Customer Care about unlocking your AT&T Mobile device:
CASE: *****
IMEI: *****

Thank you for contacting AT&T Customer Care about unlocking your device.

We cannot complete your request for one of the following reasons:

• You have not completed all the payments for your device according to your AT&T Next service agreement.

Call back, speak to rep, they tell me to submit the request via phone so I do.  I never receive a "request number".  No text or email.  Queue up another 1 on the phone with a representative only to have to submit another claim.  Same thing.  Reps have no idea how to fix a simple unlock request  Basically, you a-holes are holding my phone hostage.  Either unlock the thing or buy it back from me for what I paid almost a year ago.  

I've been dealing with this endless cycle four times so far.  I don't know how long this will continue. 

[edited for privacy-please do not post personal or unique information such as but not limited to full names, employee ID numbers, email addresses, phone numbers, account numbers, etc.]