If you have one way Audio calling your DID number, please check the following:
1. Check Service provider number - Check if calls to your number given by the service provider also have one way audio, if so please contact your service provider.
2. Check your Firewall settings - Check that your firewall settings do not block the audio traffic.
3. Try another carrier – Try to replace your service provider (you can do that by using different type of service, e.g. land-line instead of cell-phone) and verify if you are still having the problem.