Were the invited Friends new users of TurboTax, and did they complete their returns with a qualified product through the links you sent that invited them? If so, here's what the Terms say:
"Up to 45 days after an Advocate’s Friend redeems the Offer using the Link from the invitation, the Advocate will be sent an email with Reward information for electronic gift card and charity donation options (if made available). After Reward selection, another email will be sent with gift card e-certificate information..."
https://turbotax.intuit.com/referral/terms/
First check your email's spam/junk folder in case the emails ended up there. Otherwise, here's how to contact Support by phone or social media messaging.
Support hours are Mon-Fri, 5AM-5PM Pacific.
FAQ: What is the TurboTax phone number?
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
Or you can direct message a Support agent if you use social media:
https://x.com/TeamTurboTax
or
https://www.facebook.com/turbotax