Call rings in on C.O. port 3 no problem. CLEC finds channel bank to be defective. Now nothing can make C.O. port 3 ring. Sounds pretty straight forward to me. The key is, can you back it up? Did the CLEC tech SEE C.O. port 3 ring before he changed out the channel bank? If so, I'd say that's all you need. One of their representatives confirmed it was ringing as part of the troubleshooting process. Good luck with this one.

Justin