There could be several reasons for this.
1. If you have problems with inbound calls, it could be that you have not configured your phone properly. For configuration information goto our VoIP Device Help.
2. If you are diverting your number to another number, it could be that you haven't included the country code or you do not have sufficient credit to support the divert.
3. If your subscription is for a geographic number, it could be possible that your subscription has been cancelled due to some reason. Contact our support team.
4. If you have routed the number to an external destination like your PBX or another provider, please check your details and ensure that your SIP provider is not blocking traffic.
5. Loss of Internet connectivity, check with your ISP. If you have checked all of the above and the problem persists, contact our support team.