Double Payment Issue on “Media Kit” Purchase

JM “cryptotestnet” Morales 2025年10月11日

Platform: Blocklet Store Pages/Modules Affected: Payment Kit purchase, Virtual Gift Card purchase, Media Kit dependency flow Device: PC & Mobile Severity: 🔴 High (Billing / Purchase flow / UX)

🧩 Summary

Purchasing Payment Kit or Virtual Gift Card requires (or prompts to purchase) a Media Kit as a prerequisite. The system either forces users to buy a Media Kit even when they already own one, or blocks the purchase if a Media Kit is not present — leading to duplicate purchases, extra cost, or blocked checkout flows.

🪜 Steps to Reproduce

Log in to the app (Blocklet Store).
Ensure you have already purchased a Media Kit (or alternatively, start without one).
Attempt to purchase Payment Kit. Observe whether the flow:

Forces you to buy a Media Kit again, OR
Blocks purchase and prompts to buy Media Kit first.

Repeat with Virtual Gift Card purchase flow.
Note if the system:

Detects existing Media Kit ownership, or
Allows/forces an extra Media Kit purchase, or
Provides no clear info about the dependency.

✅ Expected Behavior

The system should detect if the user already owns a Media Kit and allow the purchase of Payment Kit / Virtual Gift Card without requiring the user to repurchase Media Kit.
If Media Kit is a true prerequisite, the UI must:
- Clearly show the dependency before checkout, and
- Offer to link/associate the existing Media Kit to the new product (no extra purchase).
Prevent duplicate purchases by checking entitlement server-side before charging.

❌ Actual Behavior

Users are prompted or forced to purchase a Media Kit during Payment Kit / Virtual Gift Card checkout even if they already have one.
In other cases, the purchase is blocked with no clear explanation until Media Kit is bought.
No option to associate or reuse existing Media Kit entitlement.
Customers can be charged more than once or unable to complete purchase without extra cost.

⚠️ Impact

Duplicate billing and financial loss for users.
Blocked purchases / poor conversion for products (Payment Kit, Virtual Gift Card).
Frustration and distrust — severe UX and business impact.

🔍 Possible Causes

Frontend does not check user entitlement for Media Kit before showing purchase flow.
Backend accepts purchase requests without verifying existing ownership.
Product dependency logic is missing or incorrectly implemented.
UI lacks clear messaging about prerequisites and entitlement linking.

🧰 Suggested Fixes

Enforce entitlement checks server-side before showing or enabling purchase:

if user.hasMediaKit => allow purchase
else => show clear prerequisite message with single-click purchase + auto-link

Prevent duplicate purchases by disabling/hiding the Media Kit Buy button if user.hasMediaKit == true.
Provide an “Associate existing Media Kit” flow so Payment Kit / Virtual Gift Card can reuse the Media Kit without re-purchase.
Improve UI messaging: show dependency up front (e.g., “Media Kit required — you already own Media Kit (linked) / Buy Media Kit”).
Offer bundles or combined purchase (discounted or one-click bundle) to avoid friction.
Add audit logs / billing checks to catch duplicate charges and provide admin refund workflow.