The situation could have happened in any European country and the potential buyer/victim be from almost any developing country or the US. After selecting something expensive to buy in a store and having the store attendant to confirm that the items is in stock (most of the times having the item brought to the counter), a valid credit card with sufficient credit limit is not accepted because not having the chip and PIN technology. Once the buyer explains that the policy of not swiping the cards refers to cards that have chip but does not apply to those where the chip is simply not part of the card, normally the attendant or the manager turns into "rude mode" and start to give ridiculous explanations that include phrases like "how do I know that the card is not a fake", not realizing that implying that the buyer is carrying a fake credit card is actually defamatory. But, can they do that?
One tends to think that the store can have any policy it wants regarding to which form of payment accepts and to whom it decides to sell its products, but that thought is oversimplistic and may not be necessarily correct.
Following strictly English contract law, it could be argued that the display of goods constitute an invitation to treat either when the goods are on a shop window (Fisher v Bell 1960) or on the shop's shelves (PSGB v Boots, 1953) and that the buyer makes the offer when requesting the goods (following the classic definition of offer of Carlill v Carbollic Smoke Ball, 1893), offer that the seller has the right to reject and it is normally accepted when the seller takes the payment from the buyer (as when one goes to a supermarket). In the situation in question, that would imply that when trying to pay with a "chipless" credit card the seller simply rejects the offer, but that conclusion has several problems of fact and law.
When a buyer tells the attendant that it wants to buy a particular item he or she makes the offer, which is accepted when the attendant confirms that the goods are in stock and invites the buyer to go to the counter and pay for them. In this situation, paying for the goods and receiving them are steps into the performance of the contract, which the buyer would be complying with by trying to pay with a means of payment established by implication in the same contract when the store displays the logo of the credit card in question. Accordingly, by refusing to take a valid credit card with enough limit to pay for the goods, it is the store the one breaching the contract it has with the buyer. Here it can be pointed out that even in the case of accepting that the store is breaching the contract the buyer only would get a remedy in common law in the case of suffering damages, which don't seem to exist. Still, there could be a case in equity to request specific performance, but is the criminal aspect of the situation the one that deserves further exploration.
When the store advertises a good it does so including a long list of terms that would be attached to the contract to be formed when agreement is reached with the buyer, one of them being that the buyer would be able to pay with a valid credit card that has enough limit belonging to one of the brands advertised on the store's entrance. Therefore, when the store says that its policy is to not accept valid credit or debit cards that have enough limit only because they don't have the chip and PIN technology, it is admitting that is engaging in a misleading commercial practice, as prohibited by the Consumer Protection from Unfair Trading Regulations 2008 that incorporates into English law the EU Unfair Commercial Practices Directive. Furthermore, since there are consumers that would try to look for a different means of payment instead of simply rejecting the new deal that alters the original terms, it can also be argued that the store is engaging in misrepresentation, which could be both a tort or a crime according to England's Misrepresentation Act of 1967.
But the area that could probably subject the store to a stricter legal scrutiny is discrimination, since it can be easily argued that the store in question is discriminating customers for their national origins. The store would argue that it does not discriminate customers due to their national origin because they would sell to people of any nationality that have credit or debit cards with chip and PIN technology, but since the norm, with really few exceptions, is that you need to be resident of a country to obtain a credit or debit card, those who are residents of countries where the chip and PIN technology has not been deployed are, in fact, precluded from buying in those stores. That situation would fit squarely into indirect discrimination, which "involves the application of an apparently neutral provision, criterion or practice to everyone, but it has a disproportionate effect on some people".
Finally, there is the issue of the contract between the store and the credit card brand, which clearly the store is breaching by not accepting valid credit card with sufficient credit limits only due to the use of different technology.