Once you've decided to remove, or "deactivate," your Neopets account, you will receive a message that it has been frozen if you try to log in. This is because when you choose to deactivate your account, you are essentially "freezing" it yourself.
Unfortunately, it is not possible to sign up for a new account using your old username after it has been deactivated. We also cannot completely erase any account history from our systems until the account is eligible to be purged for inactivity.
If you wish to unfreeze an account that you have deactivated, please create a "Frozen Accounts" ticket and fill out the requested information.
Thank you!