The message says I've got 1998 minutes left in my goodybag which expires on 09/09/15
That sounds like you have successfully purchased the £20 goodybag and it is active on your account.
What was it that made you think it wasn't active?
There is no access to the internet
Thanks for the update.
As you mentioned in your first post that you have taken a 2month break from giffgaff, my first suggestion would be to check that your data settings are correct.
You may need to re-setup your phone to use mobile data on giffgaff
Please follow the instructions for your handset in Settings for your device
Then post back to let us know how you are getting on.