Can you see your number, balance and goodybag here
Follow this advice and it'll resolve the problem
Did you receive more than 1 sim from giffgaff And perhaps mixed them up?
(activated the code from one sim but put the other Sim in your phone)
If that's a possibility, Try the other Sim/Sims in your phone
(switch your phone off before you remove and replace sims)
If you don't have any other Sims or those also show not active
complete these steps and it should fix the problem
(this can be completed between 4.30am and 9.30pm)
Switch your phone off and remove the sim and take note of the sim serial number on the back of the sim
Its 13 digits and printed in 3 rows starting 006 (ignore the 4Ggg4)
If you have an iPhone you don't need to remove the sim
Go to settings
Look at the number on ICCID
And Jot that down carefully on some paper,
Then double check it
there should be 19 digits
Log in here
Put that 13 or 19 digit number in the box provided
And click the yellow activate your sim button
It'll take you to a sim replacement page
Headed "SIM replacement "
Scroll down to the bottom of the page
Click where it says...
"Yes I want to replace my SIM"
On the next page click
"yes I'm sure"
On the next page you'll be asked to input a verification code to complete the sim swap
(the code will arrive to your email)
Finally on the next page click
"yes I'm sure"
The sim will usually start working within 30 minutes
(switch your phone off and on every 10 minutes or so)