diff --git a/packages/lib/server-only/user/submit-support-ticket.ts b/packages/lib/server-only/user/submit-support-ticket.ts
index 91c55800d..283cfd7b8 100644
--- a/packages/lib/server-only/user/submit-support-ticket.ts
+++ b/packages/lib/server-only/user/submit-support-ticket.ts
@@ -20,6 +20,12 @@ export const submitSupportTicket = async ({
   organisationId,
   teamId,
 }: SubmitSupportTicketOptions) => {
+  if (!plainClient) {
+    throw new AppError(AppErrorCode.NOT_SETUP, {
+      message: 'Support ticket system is not configured',
+    });
+  }
+
   const user = await prisma.user.findFirst({
     where: {
       id: userId,
@@ -52,6 +58,29 @@ export const submitSupportTicket = async ({
       })
     : null;
 
+  // Ensure the customer exists in Plain before creating a thread
+  const plainCustomer = await plainClient.upsertCustomer({
+    identifier: {
+      emailAddress: user.email,
+    },
+    onCreate: {
+      // If the user doesn't have a name, default to their email
+      fullName: user.name || user.email,
+      email: {
+        email: user.email,
+        isVerified: !!user.emailVerified,
+      },
+    },
+    // No need to update the customer if it already exists
+    onUpdate: {},
+  });
+
+  if (plainCustomer.error) {
+    throw new AppError(AppErrorCode.UNKNOWN_ERROR, {
+      message: `Failed to create customer in support system: ${plainCustomer.error.message}`,
+    });
+  }
+
   const customMessage = `
 Organisation: ${organisation.name} (${organisation.id})
 Team: ${team ? `${team.name} (${team.id})` : 'No team provided'}
@@ -60,12 +89,14 @@ ${message}`;
 
   const res = await plainClient.createThread({
     title: subject,
-    customerIdentifier: { emailAddress: user.email },
+    customerIdentifier: { customerId: plainCustomer.data.customer.id },
     components: [{ componentText: { text: customMessage } }],
   });
 
   if (res.error) {
-    throw new Error(res.error.message);
+    throw new AppError(AppErrorCode.UNKNOWN_ERROR, {
+      message: `Failed to create support ticket: ${res.error.message}`,
+    });
   }
 
   return res;