Samsung Galaxy S5 — Locked Out After Data Reset

I've had my Galaxy S5 for about 3 years now and it has reset on its own quite a few times. However a week ago when it reset I was stuck on the Setup Screen and it then asked for my Samsung Account email and password; no problem right? Wrong! Apparently it wanted the very first email account, which I no longer have, and the first password when setting up the account. Serious? Yes it was serious. I am now locked out of my phone because of this, and yes I even used a real computer to "change my email and password". I put it in quotes because it may have worked on the computer but it would not work on my phone. Why is that? I have no idea and was hoping one of y'all knew what I could do to fix my problem. I went and bought me a tablet until I get my phone fixed because I'm no longer on a contract plan but the tablet does work just as well as the phone, I just want my phone back. Lol