Make sure the person you invited has completed all of these steps.
Sign up to SeamPay using your unique referral link
Verify their identity and pass out Know Your Customer (KYC) checks
Topup their wallet with any amount
Make 6 separate purchases (airtime, data, electricity, cable etc) of at least N500 each
If your friend has performed all the above steps, a reward should already be added to your SeamPay wallet automatically.