Sounds like you're IP Banned from what you wrote. You can either try using different browsers / proxies / VPN, or you can try changing your home IP address. Depending on your ISP, you may only have to turn off / reset your modem. You may have to call your ISP and have them change it for you. There's plenty of ways around an IP ban.
My recommendation is to get Hotspot Shield, it's a good VPN that I'm pretty sure will get you past what seems to be an IP ban.
You can also subvert it by restarting your router, and if that doesn't work, look up if you can get someone from your internet supplier to change it for you.
It can't be impossible to get by- I know several people who've been Ip'd several times and just keep coming back.