I am having the exact same issue. it has been happening all night. I request to port through the Fido Portal, get the text message, reply "Yes", and 90 mins later I get a text from Fido saying that they were not authorized. Something wrong on Public Mobile side. I ported another number the same time from Chatr and it worked.
It feels like Public Mobile is holding their users hostage, preventing them to leave. Need someone at Public Mobile support to respond. I cant even get someone on the support chat.
I get a message to approve port out to fido. I send yes many times. 90 minutes later I get a message saying I didn't approve. I've done this many times.
Are you using an iPhone and iMessage? If that is the case, please make sure that the SMS option is enabled before replying to the next time that Public Mobile sends you the authorization text message.