Thank them for referring
Start with thanks, since they brought you a customer.
Check the record
Look for the referred person, the date and whether the referral conditions were met.
Explain the rule in plain words
Say what has to happen first, such as the friend's first payment, and how long the reward takes.
Fix a miss right away
If the referral was not credited, apply the reward and say when it will show.
Say no kindly when it does not qualify
Explain which condition was not met and offer a small goodwill gesture if it makes sense.
Make the rules easy to find
Link a short referral page so the next customer can check themselves.