Want to return a product without receipt - remember how long ago you purchased it. Not any thing can be brought back to the store within two weeks after purchase. But subject to the preservation packaging and presentation products. This means that the item must be unused or used even once. To return a defective purchase by law you can within the month. And for some types of goods , the return period is extended to 2 years.
Article 25 of the law "On protection of consumers 'rights" States that you can even in the absence of a cash receipt safely go to the store to hand over not approached you the goods. However, to be taken seriously, you must be a witness of the fact that you made a purchase in this store. It can be both your friend and relative who helped you to choose the thing and remembered the fact of purchase.
If there are no witnesses, as evidence of suitable branded packaging store (bags, etc.), labels and tags, etc. Suitable as a serial number recorded in the certificate store. In General, try to use any possible information available to prove that the thing purchased in the store.
Easier for those who have made a purchase through the Internet. After all, before the buyer receives his order, all the actions associated with it (shipping, payment, etc.) are recorded in the online correspondence with the customer. Usually a letter from the seller includes the serial number or the part number, size, color, model number etc. and even if the check you got, you can easily rely on these electronic data.