Referral program flop: gave $50 credits for PEX repipes and got zero new leads

Launched this referral thing last month thinking it'd boost my PEX repipe jobs, offering $50 off for each buddy they send my way with SharkBite fittings. Spent $200 on flyers and stickers just to watch it flop hard, not one damn call came in. TBH, feels like a total waste when I'm already hustlin' for those $2k bathroom remodels. Anyone got a funny story on referrals gone wrong? Saw a post in Plumbers United about this exact BS.