Hi any requests to activate your new sim with your old number made on a Friday are processed on Monday. Requests made on Saturday and Sunday are processed on Tuesday. . Please note number transfers are not carried out on weekends or public holidays e.g Bank Holiday
The number transfer process can take up to 24 hours to complete, sometimes it can be completed before 3p.m on that day.
You are required to complete the activation of the SIM card by following the steps in this https://community.giffgaff.com/t5/Getting-started/Activating-your-new-SIM/ta-p/3521635
Once the SIM is activated and you have the PAC Code from your old provider follow this http://www.giffgaff.com/support/transfer
link to the number transfer form and fill it in with the PAC code , the number you wish to transfer in and then choose the date you wish to have the number transferred into giffgaff.
On the transfer date you will experience a loss of service at some stage between the hours of approximately 9 a.m. and 9 p.m. this is no more than a few hours but may take all day, so please make plans so you're not caught out.
At some point during the day, both SIMs will stop working (may be at different times) and after a while (this could be 10 minutes or several hours) your giffgaff SIM will start working again with the transferred number. You may find that calls, texts and data start working at different times and service may be erratic until the process is complete.
While waiting for a response, try turning your phone ON and OFF every 30 mins until you get a signal
When fully activated both your mob number and any airtime credit in your goodybag will show on your dashboard https://giffgaff.com/dashboard
Hope this helps you