if you have airtime credit it will use that until zero airtime credit left.
then when that is zero you wont be able to use that function for the allowance that has run out..
you do have an option to start the next goodybag early as follows:
logon to your giffgaff dashboard here http://giffgaff.com/dashboard and you should see a link under "My goodybags" inviting you to "Start your next goodybag today"
Hi. No charges will ever be deducted from your debit card or bank. If you don't have any airtime credit (dial *100# to check)
if you run out of data and minutes (and texts if you Hsve the £5 goodybag) you won't be able to make calls or send texts or use data
Apart from calls and texts to other giffgaff numbers
And freephone numbers
You'll also still able to access giffgaff pages which are free rated
If you do run out if data or minutes you have the option of starting another goodybag early using the start today option
If you log into your my giffgaff page
You'll see the start today button just below your goodybag /goodybags once data or minutes drop below 5