Law in israel

As far as I can tell, there isn't. Israel's Consumer's Protection Act ("חוק הגנת הצרכן") states, in section 14F, that the Minister of Industry, Trade and Labor ("שר התעשייה, המסחר והתעסוקה") can set regulations that will determine when can a consumer return a product, and how will he get his money back. So far, the Minister hasn't set such regulations, so there isn't any law that forces shops to give cash-refund. 

not long ago, the knesset has passed a law that enable consumers to get their money back if they return the product in 14 days. i sugget u google it.

I'm afraid leonanidjar is somewhat mistaken. The recent amendment to the Consumer's Protection Act allows the court to order the shop to compensate the consumer in a sum of up to 10,000 NIS, in case the shop refused to comply with its own return policy and also refused to give the customer's money back. Let me explain:

According to the law (even before the recent amendment), every shop has to set a return policy (which can be cash-refund or "Zikuy"). If the shop fails to comply with that policy, a consumer can demand his money back, in the same way the customer paid (cash, credit card, etc.). Only if the shop refuses to do so, enters the new amendment and allows for a compensation of up to 10,000 NIS. that means that the law still gives the shops the first right to choose how to give a refund.

I did manage to find a news article from about a year ago (here's a link), according to which the Industry, Trade and Labor Ministry started to work on the regulations I referred to in my previous post. God knows how long that'll take. 

Special Circumstances:

You have a right to cancel the whole transaction, and get your money back, if the product appears on the list below, and the importer/manufacturer/seller did not disclose in writing to the consumer any one of the following:

1) whether there exists in Israel an inventory of spare parts for the product, or

2) the places where one can buy spare parts and the last date for purchasing spare parts, or

3) the places where one can get customer service for the product.

So, if you are canceling the transaction because the manufacturer/importer/seller did not inform you of the abovementioned information - you have a right to get your cash back.

Here's the list of products:

digital watches, cameras, electric sewing machines, blenders, mixers, vacuum cleaners, dryers, shavers, juice extractors, heaters, toasters, microwave ovens, dishwashers, personal computers, ovens, gas burners, bicycles, strollers, home air conditioners, electric toothbrushes, stove cookers, disk drives, monitors, hard drives, keyboards, printers, cartridges, scanners, video cams, telephones, radios, speakers, stereos, compact disks, tape recorders, fax machines, remote control, home cinema systems.

Regular Circumstances:

As a general rule, retailers/sellers have a right to determine the parameters for their return policy (cash or credit for future purchases, time limits, etc.) and they must post notices of this policy.  Thus, if the policy was that you can only get credit (zikuy) - you do not have a right to get cash back.  However, if you are returning the product because there is a defect of which you were not aware  - you have a right to cancel the whole transaction and get your money back.

Sources for my previous answer:

As member Roee Rotman mentioned, the main source of law is Israel's Consumer Protection Act 1981 (חוק הגנת הצרכן).

Additionally, I mentioned special circumstances which entitle you to cancel the transaction and get your money back, and the source for that is: 

תקנות הגנת הצרכן (עילות לביטול מכר) (חלקי חילוף), התשמ"ז - 1986