Freephoneline does not offer what you want. It is intended as a basic home phone replacement service.
You could use a Fongo Mobile number if you use a smartphone with Wi-Fi or cellular data to give out as a number on Kijiji.
Obihai's Auto Attendant allows you to assign PINs to specific callers to allow them to place new calls using the service providers that you've provisioned on your ATA. However, that doesn't accomplish what you want either.
You could route all blacklisted numbers to another service provider, but you'd likely have to pay to accomplish what you want. For better ideas, you can try asking at
http://www.dslreports.com/forum/voip and
http://www.obitalk.com/forum/index.php?board=4.0.
Maybe there's a workaround that escapes me at the moment.