Unlock the device

There's no point because you're dead in the water. If the phones IMEI is not registered on AT&T, the AT&T has no record of the phone being locked to AT&T. If this is a brand new phone, this means it's carrier locked but has never been used on AT&T which is a requirement to have the phone unlocked.

Where did you get this phone?

Are you in the USA? 

Thanks for your answer. I purchased the phone from the seller, Beach Camera of Amazon.

You didn’t answer all questions. Again, is it a new phone? If so, it has to be activated on ATT and meet minimum usage requirements to unlock. If you are not in the US, return the phone. 

Network unlock request unsuccessful/SIM 1 disabled...???

I bought a phone off ebay that was network locked by at&t when I put in the IMEI number online for the unlock request it comes up with a different model number and what I have and it says it's still active on an account that I needed to call customer service so I did I gave them the IMEI number they said it was eligible to be unlocked and they gave me an eight digit code to put in after I put in my T-Mobile SIM card and it says network unlock request unsuccessful they told me that I needed to call an AT&t store that they can help me fix it so I did that two of them they said they can't do anything at the online request form says it's still active on an account but AT&t customer service again told me that it was eligible to be unlocked so again they gave me the code same as before I entered it in after turning my device off putting the SIM card in charging it to full charge turning it on and then putting the code in still request for unlocked unsuccessful I just need to use my phone I don't know what to do can somebody please help me please please please I appreciate any help or any point in the right direction...???