I'm really sorry you're unhappy with how our referral bonus works. You do need £10.00 of eligible cashback in your Earnings at any status for this to track in your referrer's account. Your cashback then needs to become 'payable' for your friend's bonus to follow suit.
It may be that some of your cashback doesn't count towards the £10.00 threshold. I'll pop a link below that details the few merchants whose cashback doesn't count:
This could also be a case of the tracking chain for the bonus being broken, or if you signed up on an iPhone the bonus won't track to your friend's account (however we can check this and re-instate the bonus).
If you'd like us to take a closer look at your account and this bonus please send an e-mail in to firstname.lastname@example.org with the e-mail address of the friend who referred you.