Apparently, at the moment, porting-in number can only be done during 'new' activation of a new SIM. You cannot change your existing Fizz phone number by port-in # from another provider.
What you can do now is to order new SIM, port-in# during activation, then deactivate your existing SIM. I'm not sure what would happen with payment that you have made.
Apparently deadline of beta on Nov. 10 disappeared from FIZZ website, not sure if it is postponed. Make sure you can get the beta price before you deactivate your 'old' SIM.
Best of luck!