From your brief description, it sounds as if there is either an issue with your SIM, or a local service problem.
You can quickly confirm whether your SIM is active by checking to see if your balance and phone number are displayed on your ‘My giffgaff’ page at https://giffgaff.com/dashboard - these will not show if your SIM is inactive.
It’s important to bear in mind that, in order to keep your giffgaff SIM connected to the network, it is necessary to do at least one of the following every six months:
- make a call, or send one SMS or MMS
- connect to the internet
- make a topup/purchase (credit or goodybag)
In all cases, usage whilst outside the UK would count towards this requirement.
There are more details in the T&Cs at https://giffgaff.com/terms#Cancellation and there are more details about giffgaff’s policy on deactivating inactive SIMs at https://www.giffgaff.com/help/articles/why-is-my-phone-number-deactivated
If your SIM is showing as active on your account, but not working in your handset, you should probably check the service status in your area, which you can do by entering your postcode at http://giffgaff.com/coverage-and-service
This should give you details of any local issues, including planned and emergency engineering work, as well as indicating what sort of signal strength you should expect, and the quality of mobile internet connection. You can also check for specific mast issues and service updates there.
If you find that there are no issues reported in your area, try:
Checking for any giffgaff-specific issues in the Service Updates forum at https://community.giffgaff.com/t/service-updates
Turning your phone off, removing the SIM, waiting five minutes, then putting the SIM back in and turning your phone back on again, then wait five more minutes and try using it as normal
A manual roam (which can often sort out general communication issues) - there’s a handy guide for this at http://is.gd/manualroam
If none of the above resolves the issue, you could replace your SIM, and transfer your giffgaff account (number, credit, GoodyBag, etc) to it, by following the procedure at:
All new giffgaff SIMs can be fitted in any handset, as the smaller size ones simply pop out from the larger one.
As long as the process is started between 0430hrs and 2130hrs, it should take no more than 30 minutes, but could possibly take up to 24 hours.