fix: Fixed paddle subs

admin/internal/billing/subscription.go

@@ -2,6 +2,7 @@ package billing
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"time"
 
@@ -14,6 +15,7 @@ import (
 	"gitea.hostxtra.co.uk/mrhid6/vantage/shared/license"
 	"github.com/google/uuid"
 	"go.mongodb.org/mongo-driver/v2/bson"
+	"go.mongodb.org/mongo-driver/v2/mongo"
 	"go.mongodb.org/mongo-driver/v2/mongo/options"
 )
 
@@ -67,9 +69,21 @@ func handleSubscription(ctx context.Context, ev Event) error {
 		return fmt.Errorf("resolve items for subscription %s: %w", d.ID, err)
 	}
 
+	// Resolve BEFORE recording. A self-hosted subscription's custom_data is
+	// written at checkout and names the placeholder; the claim rewrote the
+	// instance's identity to the install's real UUID and patched Paddle, but that
+	// patch is best-effort and any event already in flight still carries the old
+	// id. Writing it straight through would revert the linked subscription row and
+	// then fail to find the instance, wedging every renewal.
+	instanceID, inst, err := resolveInstance(ctx, d.CustomData.InstanceID)
+	if err != nil {
+		return fmt.Errorf("subscription %s names unknown instance %s: %w",
+			d.ID, d.CustomData.InstanceID, err)
+	}
+
 	sub := models.Subscription{
 		AccountID:            d.CustomData.AccountID,
-		InstanceID:           d.CustomData.InstanceID,
+		InstanceID:           instanceID,
 		PaddleSubscriptionID: d.ID,
 		Tier:                 match.Tier,
 		Term:                 match.Term,
@@ -88,13 +102,6 @@ func handleSubscription(ctx context.Context, ev Event) error {
 			bson.M{"$set": bson.M{"paddle_customer_id": d.CustomerID}})
 	}
 
-	var inst models.Instance
-	if err := db.Admin("admin_instances").FindOne(ctx,
-		bson.M{"instance_id": d.CustomData.InstanceID}).Decode(&inst); err != nil {
-		return fmt.Errorf("subscription %s names unknown instance %s: %w",
-			d.ID, d.CustomData.InstanceID, err)
-	}
-
 	// Placeholders are the payment-first path: the instance does not exist until
 	// this confirmed-payment event. A cloud placeholder is provisioned here and
 	// then issued (first term). A self-hosted placeholder has no UUID to bind to
@@ -116,6 +123,27 @@ func handleSubscription(ctx context.Context, ev Event) error {
 	return promoteAndIssue(ctx, &inst, match, reason)
 }
 
+// resolveInstance finds the instance a webhook's custom_data names, following the
+// placeholder alias when the id is one a self-hosted claim has since replaced.
+// It returns the instance's CURRENT id, which is the only id anything else should
+// be written against.
+func resolveInstance(ctx context.Context, customDataID string) (string, models.Instance, error) {
+	var inst models.Instance
+	err := db.Admin("admin_instances").FindOne(ctx,
+		bson.M{"instance_id": customDataID}).Decode(&inst)
+	if err == nil {
+		return inst.InstanceID, inst, nil
+	}
+	if !errors.Is(err, mongo.ErrNoDocuments) {
+		return "", inst, err
+	}
+	if err := db.Admin("admin_instances").FindOne(ctx,
+		bson.M{"linked_from_placeholder_id": customDataID}).Decode(&inst); err != nil {
+		return "", inst, err
+	}
+	return inst.InstanceID, inst, nil
+}
+
 // promoteAndIssue promotes desired→granted from the resolved match, then signs a
 // licence from granted. This is the only promotion path other than the staff
 // grant, and it exists because a webhook is a confirmed payment.
@@ -280,9 +308,10 @@ func billingEmailFor(ctx context.Context, accountID string) string {
 
 // instanceNameFor is a best-effort display name for an email subject.
 func instanceNameFor(ctx context.Context, instanceID string) string {
-	var inst models.Instance
-	if err := db.Admin("admin_instances").FindOne(ctx,
-		bson.M{"instance_id": instanceID}).Decode(&inst); err != nil || inst.Name == "" {
+	// Alias-aware: a cancellation can name a placeholder id, and "your instance"
+	// in place of the name the customer chose reads like the wrong email.
+	_, inst, err := resolveInstance(ctx, instanceID)
+	if err != nil || inst.Name == "" {
 		return "your instance"
 	}
 	return inst.Name