Several posts on this now famous response in many stores whre sales people are either too lazy to look for the requested items, or are intimidated by the customer's demeanor or appearance. Often, the problem has to do with how locals know and refer to products so it pays to try alternate ways of asking for the same thing. As an example, when I lived there long ago, we did not ask for toothpaste but rather asked for Colgate, the dominant brand at the time. As noted in an old necro post, for some items the largest print on the label is what the product is known by locally rather than the well known brand it is known as in the West. Or the "out of stock" answer may just be the actual case. Effort to verify that product's availability doesn't seem a priority at times and the loss of said potential sale isn't a priority at stores that have plenty of business such as a pharmacy. Motivation to sell is therefore more likely to be found in smaller less popular establishments.