Unlock prepaid phone bought second hand

But no. The requirements for unlocking a phone are not different because you are not a customer. The only difference is the form has a space for do you have an AT&T phone number 'yes' or 'no'. You would feel in the bubble that says 'no'

If for any reason you cannot unlock the phone as a non-customer you will have to contact the original owner. AT&T does not assist people with unlocking second hand phones

https://www.att.com/deviceunlock/

I read online that the rules are different for devices bought second hand from an individual as long as it's not black listed or under obligation of any contract. Mine was bought second hand from an individual, isn't black listed nor under contract obligation. I don't wish to switch to att. Just would like to have it unlocked so I can use it with my carrier 

I have already provided you with the link to unlock the phone. 

Hey there! This is a tricky situation, so let's get you the information you need!

To answer your question, you will need to get in touch with the original owner of the phone to unlock the device for you. This is because the device will still be registered under his/her name. You can start using the device with your SIM card once this is done.

Hope this information helped, and thank you for visiting AT&T Community Forums!

MikeN.