You can keep your existing Google Voice number and setup Google Voice to ring your Numa number and send you text messages.
Connect Numa to your Google Voice account
Sign into the Google Voice dashboard
Click on the Settings (Gear) icon in the upper right-hand corner
Under the "Account" section, click the "New Linked Number" button
When prompted, enter the call forwarding number provided to you by Numa
Google Voice will send a text message to your Numa number with a verification code. Check Numa's inbox for this code and enter into the Google Voice verification prompt.
After verifying the phone, your Numa provided phone number will appear as a Linked Number in Google Voice
Enable Call Answering
1. In the Calls section of your Google Voice settings: Enable call forwarding to your Numa provided phone number. Note: You will need to disable Screen Calls and make sure that your Google number isn't being sent as caller ID (see screenshoot)
2. Add a call delay in Numa so that you have a chance to answer your phone before Numa picks up. In Numa go to Settings > Phones numbers > Your Numa Number > Advanced Options > Add an Artificial Delay. This is how long your phone will ring before Numa answers. If Google Voice is configured to ring multiple numbers (Recommend 15 seconds - 3 rings)
Enable Message Forwarding
Text message forwarding isn't yet in the newest version of Google Voice. Google allows you to access this in "Legacy Version". This ensures that text message sent to your Google Voice number also make it to Numa.
Go to the inbox of your Google Voice account
Click on the Menu icon (left of the Google Voice logo in the upper left-hand corner)
Choose "Legacy Google Voice" from the menu. This will open a new tab with a different looking version of your Google Voice inbox.
Click on the Settings (Gear icon) in the upper right-hand corner of your inbox. Choose "Settings" from the drop-down menu.
Under the Phones tab, your Numa provided number should be listed. Click the "Edit" button underneath the phone number
Update the name of the phone to "Numa" and change the type to "Mobile". Press the Save button
A new option should appear under the Numa phone number that allows you to "Receive text messages on this phone"; check that option
How to Confirm It's Working
You can place a test call by going to Settings > Phone numbers > Test my setup or call your business's phone number from your personal phone. If nobody answers, you should hear your Numa Voicemail greeting.
Keep in mind that Numa support must put your account into a Delayed Call Answering mode. If you don't have this setup, Numa will report incoming calls as "Missed Calls" and not answer incoming calls.
No matter what, don't hesitate to contact Numa support! We'll happily work with you and your service provider to get you all set up.