diff --git a/comebackhere-backend/src/routes/invoices.ts b/comebackhere-backend/src/routes/invoices.ts
index d728079..c60b887 100644
--- a/comebackhere-backend/src/routes/invoices.ts
+++ b/comebackhere-backend/src/routes/invoices.ts
@@ -462,7 +462,7 @@ router.get("/", validateQuery(invoiceListQuerySchema), asyncHandler(async (req:
       }
     : filter
 
-  let findCursor = collection.find(pageFilter).sort({ created_at: -1, invoice_id: -1 })
+  let findCursor = collection.find(pageFilter).sort({ created_at: -1, invoice_id: -1, _id: -1 })
   if (legacyPagination) findCursor = findCursor.skip(offset)
   const rows = await findCursor.limit(limit + 1).toArray()
   const hasMore = rows.length > limit
@@ -524,34 +524,56 @@ router.get("/", validateQuery(invoiceListQuerySchema), asyncHandler(async (req:
  *             schema:
  *               $ref: '#/components/schemas/ErrorResponse'
  */
-router.get("/:id", validateParams(invoiceIdParamSchema), asyncHandler(async (req: Request, res: Response) => {
-  const { id } = req.params
+/**
+ * Sync invoice status from contract to database (#874).
+ * Called before returning invoice details to ensure status reflects current contract state.
+ */
+async function syncInvoiceStatus(
+  invoiceId: string,
+  collection: ReturnType<typeof getInvoicesCollection>,
+  env: { invoiceContractId: string; rpcUrl: string; signerSecret: string; networkPassphrase: string }
+): Promise<InvoiceStatus | null> {
+  try {
+    const { getInvoiceStatus } = await import("./invoice-actions.js")
+    const contractStatus = await getInvoiceStatus(invoiceId, {
+      rpcUrl: env.rpcUrl,
+      invoiceContractId: env.invoiceContractId,
+      signerSecret: env.signerSecret,
+      networkPassphrase: env.networkPassphrase,
+    })
+
+    // Update the database with the current contract status
+    await collection.updateOne(
+      { invoice_id: invoiceId },
+      { $set: { status: contractStatus, updated_at: new Date() } }
+    )
 
-  const env = requireEnv({ invoiceContractId: "INVOICE_CONTRACT_ID" })
+    return contractStatus
+  } catch (err) {
+    // If we can't fetch from contract, return null to fall back to DB status
+    return null
+  }
+}
 
-  const server = new SorobanRpc.Server(env.rpcUrl)
-  const contract = new Contract(env.invoiceContractId)
+router.get("/:id", validateParams(invoiceIdParamSchema), asyncHandler(async (req: Request, res: Response) => {
+  const { id } = req.params
 
-  // Build a read-only ledger entry query for the invoice
-  const ledgerKey = contract.getFootprint()
-  void ledgerKey // used below via getLedgerEntries
+  const env = requireEnv({ invoiceContractId: "INVOICE_CONTRACT_ID", rpcUrl: "SOROBAN_RPC_URL", signerSecret: "SIGNER_SECRET_KEY", networkPassphrase: "NETWORK_PASSPHRASE" })
 
-  // Query the contract's ledger entry directly
-  const entries = await server.getLedgerEntries(
-    xdr.LedgerKey.contractData(
-      new xdr.LedgerKeyContractData({
-        contract: new Contract(env.invoiceContractId).address().toScAddress(),
-        key: nativeToScVal(BigInt(id), { type: "u64" }),
-        durability: xdr.ContractDataDurability.persistent(),
-      })
-    )
-  )
+  const db = await connectMongo()
+  const collection = getInvoicesCollection(db)
 
-  if (!entries.entries.length) {
+  // Get the invoice from database
+  const invoice = await collection.findOne({ invoice_id: id })
+  if (!invoice) {
     throw new NotFoundError("Invoice not found")
   }
 
-  res.json({ invoice_id: id, status: "Pending" })
+  // Sync status from contract to ensure it reflects any settlement (#874)
+  const contractStatus = await syncInvoiceStatus(id, collection, env)
+  const status = contractStatus || invoice.status
+
+  res.json({ invoice_id: id, status })
 }))
 
 /**
@@ -725,6 +747,16 @@ router.post("/", requireMerchantApiKey, validateBody(createInvoiceSchema), async
 
   const db = await connectMongo()
   const collection = getInvoicesCollection(db)
+
+  // Check for duplicate invoice ID to prevent conflicts (#877)
+  const existing = await collection.findOne({ invoice_id: result.invoice_id })
+  if (existing) {
+    throw Object.assign(
+      new Error(`Invoice ID ${result.invoice_id} already exists; please retry to generate a new ID`),
+      { status: 409 }
+    )
+  }
+
   const now = new Date()
   await collection.insertOne({
     invoice_id: result.invoice_id,
diff --git a/comebackhere-backend/src/schemas/index.ts b/comebackhere-backend/src/schemas/index.ts
index 762ad4d..59c63e3 100644
--- a/comebackhere-backend/src/schemas/index.ts
+++ b/comebackhere-backend/src/schemas/index.ts
@@ -28,6 +28,9 @@ const futureTimestamp = z
   .refine((val) => val > Math.floor(Date.now() / 1000), {
     message: "due_date must be in the future",
   })
+  .refine((val) => val <= Math.floor(Date.now() / 1000) + 315_360_000, {
+    message: "due_date must be within 10 years from now",
+  })
 
 export const createInvoiceSchema = z.object({
   token: z.string().min(1, "token is required"),