If you purchased a goodybag,it doesn't appear on your "balance"-they're completely different things.
Airtime credit (your "balance") is for standard PAYG rates and items not included in any goodybag,eg,premium rate calls,calls/texts to international numbers,MMSs,calls to 101,etc.Airtime credit remains on your account until used.
Goodybags are bundles of UK minutes,texts and data and last for a month.
Call 43430 (top up number,free to call from an active giffgaff sim),select option 2 and listen to the recorded message.
What does it tell you?
my boyfriend referred me, and the screen says £15 paid, and £15 being taken next month, but only a balance of £5 on my account, is there a £10 fee for joining?
No,there are no "joining fees".
The £15 you've paid (and set up for next month) is your goodybag.
What exactly are you told when you call 43430 and select option 2?