diff --git a/apps/web/lib/coinpay.ts b/apps/web/lib/coinpay.ts
index 8dca2fe..c0bef16 100644
--- a/apps/web/lib/coinpay.ts
+++ b/apps/web/lib/coinpay.ts
@@ -46,6 +46,7 @@ export async function createCoinpayPayment(args: {
     }
     return { ok: true, payment: data.payment };
   } catch (err) {
+    console.error(`[coinpay] create payment failed:`, (err as Error).message);
     return { ok: false, error: (err as Error).message };
   }
 }
@@ -57,10 +58,14 @@ export async function getCoinpayPayment(id: string): Promise<CoinpayPayment | nu
     const res = await fetch(`${env.coinpay.baseUrl}/payments/${id}`, {
       headers: { Authorization: `Bearer ${env.coinpay.apiKey}` },
     });
-    if (!res.ok) return null;
+    if (!res.ok) {
+      console.error(`[coinpay] status fetch failed for ${id}: HTTP ${res.status}`);
+      return null;
+    }
     const data = (await res.json()) as { payment?: CoinpayPayment } & CoinpayPayment;
     return data.payment ?? (data.id ? data : null);
-  } catch {
+  } catch (err) {
+    console.error(`[coinpay] status fetch error for ${id}:`, (err as Error).message);
     return null;
   }
 }
diff --git a/apps/web/lib/entitlements.ts b/apps/web/lib/entitlements.ts
index 3d1c484..27c2e79 100644
--- a/apps/web/lib/entitlements.ts
+++ b/apps/web/lib/entitlements.ts
@@ -123,26 +123,21 @@ export async function quotePromo(
   if (row.max_uses != null && Number(row.uses) >= Number(row.max_uses)) {
     return { ok: false, error: "This code has been fully redeemed." };
   }
-  const dup = await sqlClient.execute({
-    sql: "SELECT 1 FROM promo_redemptions WHERE code = ? AND user_id = ? LIMIT 1",
-    args: [code, userId],
-  });
-  if (dup.rows[0]) return { ok: false, error: "You've already used this code." };
-
   const percentOff = Math.min(100, Math.max(1, Number(row.percent_off ?? 100)));
   const finalUsd = round2(baseUsd * (1 - percentOff / 100));
   return { ok: true, code, percentOff, baseUsd, finalUsd, free: finalUsd <= 0 };
 }
 
-/** Record a promo redemption (idempotent). Call once the discount is actually granted. */
-export async function recordPromoRedemption(codeRaw: string, userId: string): Promise<void> {
+/** Record a promo redemption (idempotent). Returns true if newly recorded. */
+export async function recordPromoRedemption(codeRaw: string, userId: string): Promise<boolean> {
   const code = codeRaw.trim().toUpperCase();
-  if (!code) return;
+  if (!code) return false;
   try {
     await sqlClient.execute({ sql: "INSERT INTO promo_redemptions (code, user_id) VALUES (?, ?)", args: [code, userId] });
     await sqlClient.execute({ sql: "UPDATE promo_codes SET uses = uses + 1 WHERE code = ?", args: [code] });
+    return true;
   } catch {
-    /* already recorded — composite PK makes this a no-op */
+    return false;
   }
 }
 
diff --git a/apps/web/lib/password.ts b/apps/web/lib/password.ts
index 685767b..3e105e7 100644
--- a/apps/web/lib/password.ts
+++ b/apps/web/lib/password.ts
@@ -1,9 +1,9 @@
 import { hash, verify } from "@node-rs/argon2";
 
-// Argon2id parameters — reasonable defaults for interactive auth.
+// Argon2id parameters — OWASP recommended minimums for production.
 const opts = {
-  memoryCost: 19456,
-  timeCost: 2,
+  memoryCost: 47104,
+  timeCost: 3,
   parallelism: 1,
 } as const;