You can check your Incentive history by logging into the website and clicking on History. Your referred people will be listed here.

If they are not in your list they have not used your referral link.

We are not able to give any details about other members, so if you are certain that something has gone wrong with the referral process you will need to get your referrals to email and ask to have their account linked to their referrer. They will need to include your referral link and the email should be from their registered account.