I apologize for the confusion regarding our ability to support the Sonic Mobile Communicator. This is still a supported feature.
Since you are running into an issue with logging in the best thing to do is going to be the following.
1. Log into https://members.sonic.net
on a desktop or laptop is easiest
2. Click the voice tab on the left hand side
3. Click your phone number under the Phone Number List section
4. You'll see a green and blue interface known as Commportal and locate View Account Settings near the bottom right corner
5. Click Change Password under the Security section
6. Enter your new password and confirm the password and make sure to click confirm.
7. You should then be able to log in with the new password on your Sonic Mobile Communicator App
You can also view the Sonic Mobile Communicator page here https://help.sonic.com/hc/en-us/articles/236117267-Sonic-Mobile-Communicator