MaxoTel requires each device (i.e Desk Phone, Cordless Phone, App, or Softphone) to be registered as a separate Extension on the Hosted PBX. If multiple devices are registering to the same extension number, then there will be problems sending incoming calls to the devices as the server will only send calls to the last device that connected with that username/password.
You can upgrade your plan to add more extensions to your Hosted PBX.
On a Hosted PBX, to set up 'twinning', where a call rings in more than one place, you can use a personal ring group. To do so;
Once complete, when anyone calls your main extension number, the call will ring on all agents configured in the ring group simultaneously. For more information on the ring group's settings, please see Portal Guide - Ring Groups