Transacting through e-commerce giants like Shopee and Lazada is governed by a robust framework of Philippine laws designed to protect consumers from fraud, defective products, and deceptive sales practices. If a dispute arises and the platform's internal resolution system fails, consumers have clear legal avenues for redress.

1. Governing Laws

Consumer rights in the Philippines are primarily protected by:

Republic Act No. 7394 (The Consumer Act of the Philippines): The primary law protecting against deceptive sales acts and substandard products.
Republic Act No. 10175 (Cybercrime Prevention Act of 2012): Relevant if the seller engages in identity theft or hacking.
Republic Act No. 11967 (Internet Transactions Act of 2023): This recent law specifically mandates that e-commerce platforms and online sellers are liable for consumer protection, ensuring that digital transactions are held to the same standards as brick-and-mortar sales.

2. Pre-Legal Step: Platform Mediation

Before escalating to government agencies, you must exhaust the internal dispute resolution mechanisms provided by the apps:

The "Return/Refund" Button: Both platforms have a "Safe" period (Shopee Guarantee or Lazada’s Return Window). Do not click "Order Received" if the item is defective or missing.
Evidence Collection: Document the unboxing through video. Screenshot all conversations with the seller. Save the Waybill (the sticker on the package).
Customer Service (CS): If the seller refuses a refund, "Raise to Agent" or "Escalate to Shopee/Lazada." Under the Internet Transactions Act, platforms are now subsidiarily liable if they fail to exercise due diligence in vetting sellers.

3. Filing a Formal Complaint with the DTI

If the platform or seller denies a valid claim, the next step is filing a complaint with the Department of Trade and Industry (DTI).

A. Grounds for Complaint

Deceptive Sales Act: The item received is significantly different from what was advertised.
Defective Products: The item is broken, non-functional, or unsafe.
Non-Delivery: The seller took payment but failed to ship the item.
No "No Return, No Exchange" Policy: This policy is illegal under the Consumer Act.

B. The Process

Submit a Complaint: Use the DTI’s FTEB (Fair Trade Enforcement Bureau) portal or email consumercare@dti.gov.ph.
Required Information:

Full name and address of the complainant.
The store name and, if possible, the seller's business address (platforms are required to provide this upon request for legal disputes).
A brief narration of facts.
Proof of transaction (Order ID, screenshots of the listing, and chat logs).

Mediation: The DTI will schedule a mediation conference (often via Zoom) where both parties and a DTI mediator discuss a settlement (e.g., refund, replacement).
Adjudication: If mediation fails, the case proceeds to adjudication, where a DTI officer will issue a formal decision. Sellers found in violation can face administrative fines and the revocation of their business permits.

4. Criminal Complaints for Fraud (Estafa)

If the seller intentionally defrauds you (e.g., sending a rock instead of a laptop or engaging in a "bait-and-switch" scam), this may constitute Estafa under the Revised Penal Code, in relation to the Cybercrime Prevention Act.

Where to go: The PNP Anti-Cybercrime Group (PNP-ACG) or the NBI Cybercrime Division.
Action: You will need to execute a formal affidavit and provide electronic evidence. This is a criminal path and is generally reserved for high-value scams.

5. Small Claims Court

For disputes involving money (refunds) not exceeding PHP 1,000,000, you can file a case in a Small Claims Court.

No Lawyers Required: The process is designed to be inexpensive and fast.
Procedure: You fill out forms (Statement of Claim) and file them in the Metropolitan or Municipal Trial Court of your city. If the court rules in your favor, it can issue a writ of execution to force the refund.

6. Key Reminders for Consumers

Official Receipts: Under Philippine law, sellers (especially those with high volume) are required to issue a sales invoice or official receipt.
Data Privacy: Sellers are prohibited from "doxing" or publicly shaming you for returning items under the Data Privacy Act of 2012.
The Price Tag Law: Items must have a clear price. "PM for price" is technically a violation of the Consumer Act, although difficult to enforce individually.