Wrong...
You need to understand what a "bad ESN" is first. A "bad ESN" is an ESN tied to a device that is either active on an account (in use) or locked to an account, either because of TOS violations, or failure to pay the ETF.
If you check the ESN of a phone you are currently using, it should say it has a BAD ESN because it's active, meaning someone else can't just grab that ESN and activate it on their account.
If you check an ESN and it says it is CLEAN, this means the ESN is not tied to an account, making it eligible for activation on an account.
Now, the addition of the "Not Postpay" notification, this notification is given to us by Sprint, stating that the ESN is no longer listed on Sprint's PostPay database. This should occur when you check a Sprint MVNO ESN, such as Boost Mobile, Virgin Mobile, Credo, iWireless, etc... it can also occur when you enter the ESN of a Sprint device that has been migrated away from Sprint's PostPay database to a Sprint PrePay MVNO such as PlatinumTel, PrepaYd Wireless, etc.
Please make sure you understand how things work before you say bad things about it.
-Shane
/www.CheckESNFree.com/