Carriers use billing documents to prove that you own the phone number(s) you are attempting to port. Without correct documentation, your port request can be rejected.
If you are porting a Google Voice number…
Please take a screenshot of the Google Voice settings page making sure the phone number and your email address appear in the screenshot.
If you are porting a Toll Free, Landline, or VoIP number…
Please send us your latest monthly bill which includes the phone number(s). If your provider does not provide you with a bill, please provide a receipt of phone number purchase and/or a screenshot of your account portal with the phone numbers included.