Email dunning has been the default for a decade. It's cheap, it's easy, and every billing platform ships with it. But cheap and easy is not the same as effective.
The benchmark study
We pulled anonymized data from 12,400 failed-payment recovery attempts across 47 agencies and B2B SaaS companies using DunningJet. The results were not close.
Email-only dunning sequences recovered 14% of failed payments within 7 days. SMS-only flows recovered 61%. Combined SMS + email recovered 67%. The headline: SMS recovered 4.3× more revenue than email in the same time window.
Why the gap is so large
Open rates. Industry-average B2B email open rates sit at 22% and dunning emails are routinely filtered as transactional spam. SMS messages have a 98% open rate and are typically read within 3 minutes of delivery.
When you're recovering a payment, time-to-read is everything. The longer the gap between failure and the customer fixing it, the more likely they churn entirely.
The cost trade-off, honestly
SMS costs money per message (around $0.0079 in the US via Twilio). For a $99/mo subscription, that's a rounding error. For a $5/mo product, you'll want to be selective.
DunningJet lets you set a minimum invoice amount before triggering SMS so the unit economics always work in your favor.