First thing is to check in the order history section of https://giffgaff.com/profile/payment-details that you did actually buy a goodybag. If it says topup rather than goodybag, you bought only PAYG credit. It's important to always buy goodybags starting from https://giffgaff.com/buy/goodybag or by dialling 43430 option 2 not option 1.
Never add credit (via the topup option) before buying your goodybag -- if you do there are two dangers:
- if you have no other credit, and no remaining goodybag data, your phone is likely to use some of your credit to perform outstanding tasks such as checking for updates or downloading emails. This will probably happen before you have time to buy the goodybag, and will use a few pence of the credit, probably leaving you with insufficient credit to buy the goodybag
- members often forget to buy the goodybag from the credit they added
However, if you've already added credit by mistake, it's not guaranteed but on the first occasion agents will often give a small discretionary credit if you explain what you have done at https://support2.giffgaff.com/app/ask/Top-up-balances-and-goodybags/goodybag-allowances-or-credit-balance-incorrect/