Locked out of iPhone! What do I do?

So I have an iPhone 5s and I enabled the touch thing where your finger unlocks it. Well, I went ahead and tried to put in a passcode because it had been a while since I used it and I wanted to make sure I remembered it. Well, it was wrong and I kept trying different ones because I was sure it was within the 1245 range. Well none of them worked so now I'm locked out and I have no idea what the passcode could be bacause I made it so long ago. The touch thing doesn't even work and so now I'm so mad. How to I unlock it? Do I need to go to AT&T, will they be able to unlock it for me? I have the original box and everything. Or am I forever locked out of my expensive iPhone?

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