FNB & ICASA failed me. For almost a year my SIM still can’t receive simple SMS

I have an FNB Sim Card that since October 2020 hasn’t been able to receive SMSs. I’ve been from pillar to post with them, even swapped the Sim Card but now it’s August 2021, they’re unable to solve it, and they’re now no more calling me to resolve it. I’m unable to port my number because I can’t receive an SMS to for OTP or anything to enable the porting. I’ve written to ICASA & Department of Communications via Twitter, they also never responded to this day. How may I port to Telkom?