It's the account aswel. I've tried many things from IP changers, hotspur shield, to even calling my ISP, but nothing works. Don't bother because you won't get anywhere. Now, there is a chance though. Submit a ticket to Nexon. Tell them you want to buy NX through Paypal but for some reason you can't because it seems like you got banned from it. Add details to this and try and convice them.