Welcome to Android Central! FYI, I moved your post from an existing (and very very old thread from the AT&T Galaxy S III forum) to its own thread in the Ask A Question forum.
For further context for anyone else seeing this thread, you previously PM'd me a request to help you network unlock your Galaxy A02. We're unable to do this for you on this forum. If the phone is network locked, then you need to satisfy the unlock criteria for the network that it's locked to. If you tell us which carrier it's locked to, we can look that policy up for you.
But if you have not met the criteria for unlocking, then you're stuck. That criteria is there for a reason -- typically these phones are offered very cheap or "free" on the condition that it's used on that carrier's network for a certain amount of time (usually 6-12 months) before it can be unlocked.