Let me clear up some cob webs in this forum...

1. The Law?

You can throw all this out the window, since there a minimum amount that can be claimed before a Magistrate and its way too costly to pursue a legal action.

Contracts Act?
Sales of Goods Act?
Interpretation Act?
Penal Code (on Fraud,Cheating whatnot)
Limitation Act?

2. What about Consumer Associations?

CASH
Consumer Tribunal
CFM (Consumer Forum Malaysia)

etc...

They have no application in this forum, so dont bother running to them unless of course the Seller is a Mechant has a store/retail outlet/company and the amount is substantial.

And of course Receipts of purchase, proof of postage etc...

3. For a more practical aspect?

Basically there is no legal remedy unless:
a. it involves criminal elements; and/or
b. the amt is significant; and
c. have the paper works and documentation available as evidence i.e. receipt of purchase.

Early steps of preventing yourself from being a victim is essential to avoid sticky situations like this. So do the reading all the essential info is listed in the forum.