Naked Mobile is a brand by Clear Talk. To port a phone number away from Naked Mobile, you will need the account number and PIN that Naked Mobile originally set up when activating your account. Clear Talk customer service seems like the best way to get this information although it looks like the company is going through major changes.
Frontier Communications does Porting in and out from mobile phone accounts. You will need the Account number, PIN/password, and verification that you are the owner of both accounts (mobile service and Frontier Communications). All of this can be done over the phone with Customer Service.