1) Vonage Extensions is almost equivalent in functionality to CallsUnLtd.
2) With Vonage extensions, call forwarding interface is also changed (captcha introduced for international numbers). This means the interface change needs to be incorporated.
3) We are happy to have inspired the creation of an awesome product - Vonage Extensions.
4) At this time, unless there is strong customer demand to resurrect CallsUnLtd, we will end-of-life CallsUnLtd.
Enjoy Vonage, hope they keep innovating.