diff --git a/backend/src/billing.rs b/backend/src/billing.rs
index 448bd59..90c968c 100644
--- a/backend/src/billing.rs
+++ b/backend/src/billing.rs
@@ -44,6 +44,9 @@ impl BillingService {
             if let Err(err) = self.bill_tenant(&tenant).await {
                 tracing::error!(tenant = tenant.pubkey, error = %err, "billing failed");
             }
+            if let Err(err) = self.suspend_if_delinquent(&tenant).await {
+                tracing::error!(tenant = tenant.pubkey, error = %err, "grace period enforcement failed");
+            }
         }
         Ok(())
     }
@@ -105,6 +108,32 @@ impl BillingService {
         Ok(())
     }
 
+    async fn suspend_if_delinquent(&self, tenant: &Tenant) -> Result<()> {
+        if tenant.status != "active" {
+            return Ok(());
+        }
+
+        let invoices = self.repo.list_invoices_by_tenant(&tenant.pubkey).await?;
+        let latest = match invoices.first() {
+            Some(invoice) => invoice,
+            None => return Ok(()),
+        };
+
+        if latest.status != "pending" {
+            return Ok(());
+        }
+
+        let created_at = parse_timestamp(&latest.created_at)?;
+        let deadline = created_at + chrono::Duration::days(7);
+        if Utc::now() < deadline {
+            return Ok(());
+        }
+
+        self.repo.update_tenant_status(&tenant.pubkey, "suspended").await?;
+        self.repo.suspend_relays_for_tenant(&tenant.pubkey).await?;
+        Ok(())
+    }
+
     async fn make_invoice(&self, amount: i64) -> Result<String> {
         if self.platform_nwc_url.trim().is_empty() {
             return Err(anyhow!("NWC_URL is required to generate invoices"));
diff --git a/backend/src/repo.rs b/backend/src/repo.rs
index 23354a9..6a10682 100644
--- a/backend/src/repo.rs
+++ b/backend/src/repo.rs
@@ -122,6 +122,14 @@ impl Repo {
         Ok(())
     }
 
+    pub async fn suspend_relays_for_tenant(&self, tenant: &str) -> Result<()> {
+        sqlx::query("UPDATE relays SET status = 'suspended' WHERE tenant = ? AND status = 'active'")
+            .bind(tenant)
+            .execute(&self.pool)
+            .await?;
+        Ok(())
+    }
+
     pub async fn get_relay(&self, id: &str) -> Result<Option<Relay>> {
         let relay = sqlx::query_as::<_, Relay>(
             "SELECT id, tenant, name, subdomain, schema, icon, description, plan, status FROM relays WHERE id = ?",