When porting takes place, routing updates need to occur. Some carriers take awhile to fully update routes, and random issues, such as what you witnessed, can occur.
Porting notifications go to NPAC (Number Portability Administration Centre) and once activated, the porting changes get broadcasted to CLECs (Competitive Local Exchange Carrier, such as Fibernetics), or, at least, that's my understanding. The updates are supposed to happen automatically, but for whatever reason, Fibernetics' (parent company of Freephoneline) interval for updates seems to be a bit slower than with some other companies. I find these types of issues typically resolve within 24 to 48 hrs.
If the issue isn't resolved by Tuesday, submit a ticket:
https://support.fongo.com/hc/en-us/requests/new.