My number was ported a couple months ago and I had to fax an authorization form.

This is from the Voipo knowledge base:

We are able to port your existing number at no additional costs. Please note that the process will take 1-2 weeks, and in extreme scenarios it may take up to 45 days. To initiate the the process, please provide the required information:
•Letter of Authorization: http://voipo.com/Porting.pdf

•Copy of a Recent Bill (or print out of your account) verifying your name and number with the losing carrier.
Fax these to 832-426-7700 or e-mail them to support@voipo.com and we will quickly submit them to our port processing authority. You can assign your account a temporary incoming number (virtual number) while the porting process is underway.