Hello,
I'm very sorry to hear your having signing in troubles on PSN. The same problem happened to me, so I called PSN and explained to them what happened. They un-banned my account and I can use it whenever I want.
Problem:
I was off to vacation for a month and handed my account over to my cousins. When I came back the account was temporarily banned. I contacted support over phone and we had a nice little conversation about my account and why it could have been banned. I was un-banned shortly after.
Solution:
I don't know where you live, but I would contact support if I were you. But I went to this link for help:
You must login or register to view this content.
Try sending them an email first, and most likely they will ask you to call them. Give them a quick call and you will be unbanned in no time. All bans that take place are for a reason, if you aren't aware of this reason just be honest with them. You can never lie your way around support.
Best of luck,
PcChip