Sorry to read of your situation this morning. That is correct, a SIM Swap procedure usually takes around a few minutes to 24 hours to complete though the system in full. However, the “norm” is around 30 minutes complete. Please reboot your device after 30 minutes until your SIM card registers on the Giffgaff network again.
If you are now beyond 24 hours and SIM Swap has not completed successfully, you have done the correct in contacting an Agent for assistance.
Contact an Agent (SIM Swap procedure problem) >> https://support2.giffgaff.com/app/ask/SIM-and-number/Performing-a-SIM-Swap/form/
For further information Giffgaff’s SIM Swap facility, which includes a video tutorial, please follow this link (What is SIM Swap) to view.
Good luck to you.