So my previous router was in dire need to being replaced so I have done so, and plugged it in and got it up and running last night. I tested the phone to see if there was a dial tone which there was, so thought all was good. 
However when calling the phone it goes straight to voicemail and when calling from the phone the person who is being called cannot hear anything. 

I have powered off/on the ATA, which made no difference. Any ideas? Does this sound like a rule that I have enabled or not enabled as the case may be?