My Nextel is stolen or lost!!! : * (
Can i like blacklist the handset?
You should definately report it as stolen to your carrier. But don't expect much action on getting it returned.
The IMEI (msn) will show up in an open and active account when somebody try's to activate it, but there are ways around that issue, the activating agent should act responsibly and tell the customer to contact Nextel to get them to release it before he/she can activate the equipment, but....